Shun Lu, Yuan Liu, Hong Liu · Progress in Chemistry · 2024
Mini-review of conductive phthalocyanine-based metal-organic frameworks as electrocatalysts, with emphasis on charge-transport mechanisms, representative electrocatalytic reactions, and remaining activity, conductivity, selectivity, and stability challenges.
The review’s argument is preserved as a navigable set of section summaries.
Organises future needs around catalytic activity, conductivity, selectivity, and stability, and recommends mechanism-resolved characterisation, theoretical calculations, morphology control, structural engineering, and durable active-site design.
Relevance: Core · 293 · 4 Challenges and outlook · Fig. 9
Concludes that phthalocyanine-based c-MOFs combine heterogeneous electrocatalyst advantages with high porosity, crystallinity, conductivity, and dense active sites, but further progress depends on resolving active-site mechanisms and stability.
Relevance: Core · 295 · 5 Conclusion
Summarises charge transport in phthalocyanine c-MOFs using conductive-MOF concepts: conductivity depends on carrier mobility and concentration, with band-like and hopping mechanisms and several structural pathways for charge transfer.
Relevance: Core · 288 · 2 Conductive mechanisms · Figs. 2-3
Reviews phthalocyanine-based c-MOF examples in HER/OER, ORR, CO2RR, NRR, and other redox reactions, consistently linking electrocatalytic performance to active-site accessibility, conductivity, porous mass transport, and tunable metal/linker chemistry.
Relevance: Core · 289 · 3 Electrocatalysis
Frames electrocatalysis as a sustainable route for energy and environmental applications, identifies low conductivity in conventional MOFs as a bottleneck, and defines phthalocyanine-based c-MOFs as a relatively overlooked conductive MOF subclass.
Relevance: Core · 287 · 1 Introduction · Fig. 1
Extends the review's application framing beyond the main reactions to UOR, hydrazine oxidation, and biomass oxidation, while warning that reaction-specific conditions must guide c-MOF design.
Relevance: Supporting · 293 · 3.5 Other possible reactions
Classification systems are attributed to this review and are not treated as a global material registry.
The outlook groups barriers to practical phthalocyanine c-MOF electrocatalysts into activity, charge transport, product/pathway selectivity, and operational durability.
Categories: Catalytic activity · Conductivity · Selectivity · Stability
293 · 4 Challenges and outlook · Fig. 9
The review groups conductivity-enhancing structural motifs around through-bond, extended-conjugation, through-space, redox-hopping, and guest-assisted charge transfer.
Categories: Consecutive coordination bonds · Two-dimensional metal-organic analogues · Through extended conjugated frameworks · Through-space p-p interactions · Redox hopping · Guest-promoted pathways
288 · 2 Conductive mechanisms · Figs. 2-3
The application taxonomy follows the review's sectioning and covers water splitting, oxygen, carbon dioxide, nitrogen, and possible small-molecule or biomass oxidation reactions.
Categories: Hydrogen evolution reaction · Oxygen evolution reaction · Oxygen reduction reaction · Carbon dioxide reduction reaction · Nitrogen reduction reaction · Other oxidation reactions
286 · Contents
The review briefly classifies available synthesis approaches but states that synthesis is not its main focus.
Categories: Top-down approaches · Bottom-up approaches · Exfoliation · Interfacial synthesis · Layer-by-layer deposition · Solvothermal treatment · Surfactant-assisted synthesis
287 · 1 Introduction
The review adopts the conductive-MOF distinction between continuous-band transport and hopping between localised states, while noting that assigning either mechanism is difficult in defective crystalline MOFs.
Categories: Band-like transport · Hopping transport
288 · 2 Conductive mechanisms
Review-defined families retain their representative materials and conduction descriptions.
Phthalocyanine-based c-MOFs whose electronic configuration is modulated by introducing dual metal clusters into the framework.
Conduction: Electronic interactions between Ni-O4 and Ni-N4 clusters are interpreted through DOS/PDOS and linked to improved OER behaviour.
Representative materials: NiPc-Ni c-MOF · MPc-M' c-MOFs
Nodes / linkers: Ni-O4 · Ni-N4 · Zn-containing clusters · Metallophthalocyanine linkers · Dual-metal cluster linkages
290 · 3.1 Water electrolysis · Fig. 5
Metallophthalocyanine-pyrene frameworks connected by pyrazine linkages and varied metal centres.
Conduction: Columnar porous stacking and high in-plane conjugation enable fast electron transfer while M-N4 sites tune competing HER and NRR kinetics.
Representative materials: FePc-pz · CoPc-pz · NiPc-pz · MnPc-pz · ZnPc-pz · CuPc-pz
Nodes / linkers: Fe-N4 · Co-N4 · Ni-N4 · Mn-N4 · Zn-N4 · Cu-N4 · Metallophthalocyanine units · Pyrene units · Pyrazine linkages
292 · 3.4 N2 reduction reaction · Fig. 8
Porous NiPc-based c-MOFs connecting planar NiPc motifs through NiN4 nodes.
Conduction: Conductivity is attributed to d-p conjugation between NiN4 nodes and NiPc-substituted o-phenylenediamine, producing electron delocalisation.
Representative materials: NiPc-NiN4 c-MOFs
Nodes / linkers: NiN4 nodes · NiPc centres · NiPc-substituted o-phenylenediamine · d-p conjugated NiN4 linkages
287 · 2 Conductive mechanisms
NiPc-based c-MOF nanosheets with NiO4 linkages and in-plane full p-d conjugation.
Conduction: Strong conductivity is attributed to in-plane full p-d conjugation between NiPc and NiO4 linkages.
Representative materials: NiPc-NiO4 c-MOF nanosheets
Nodes / linkers: NiPc nickel centre · NiO4 linkages · Octa-aminophthalocyaninato Ni(II) · NiO4 linkages
292 · 3.3 CO2 reduction reaction · Fig. 7
CuPc-based conjugated c-MOFs using square-planar metal bis(dihydroxy) complexes as linkages.
Conduction: Porous structure and extensive electrochemically active Co-site coverage support ORR activity, with in situ Raman used to identify cobalt-node active sites.
Representative materials: PcCu-O8-Co · PcCu-O8-Co/CNT
Nodes / linkers: CuPc · Co-O4 · Fe · Ni · Cu · Co bis(dihydroxy) linkages · O8 coordination motif
291 · 3.2 Oxygen reduction reaction · Fig. 6
Layer-stacked porous conductive MOFs built from phthalocyanine complexes and conjugated coordination linkages.
Conduction: In-plane extended conjugation and interlayer interactions facilitate electron or charge transfer while pores support mass diffusion.
Representative materials: NiPc-based c-MOFs · MPc-pz · NiPc-NiO4 c-MOF · PcCu-O8-M c-MOF
Nodes / linkers: Ni · Fe · Co · Cu · Mn · Zn · Phthalocyanine ligands · M-N4 linkages · M-O4 linkages · Pyrazine linkages
286 · Abstract
Review-level synthesis principles remain separate from primary-study recipes.
The review repeatedly argues that metal centres, linkages, and microenvironmental modulation should be rationally tuned to optimise conductivity, active-site exposure, and reaction selectivity.
Claimed effects: Can improve charge transfer, expose more active sites, and shift adsorption/desorption energetics for target electrocatalytic pathways.
Controlling variables: MPc metal centre · Organic linkage · Metal node oxidation state · Microenvironmental electronic state · Active-site exposure
Representative materials: NiPc-NiO4 c-MOF · FePc-pz · PcCu-O8-Co
Caveat: The review frames this as a future design principle; primary studies remain needed for reaction-specific validation.
290 · 3.1 Water electrolysis
Solvothermal synthesis is used to assemble MPc and pyrene units into MPc-pz and to prepare layer-stacked PcCu-O8-Co structures.
Claimed effects: Provides crystalline layered porous c-MOFs with tunable M-N4 sites for NRR/HER competition and ORR-active metal nodes.
Controlling variables: Metallophthalocyanine metal centre · Pyrazine linkage formation · Solvothermal conditions · Metal-linkage choice
Representative materials: MPc-pz · PcCu-O8-Co
Caveat: The review reports outcomes and design logic, not full recipes.
292 · 3.4 N2 reduction reaction · Fig. 8
Electronic configurations of phthalocyanine c-MOFs can be tuned by introducing dual metal clusters into the matrix.
Claimed effects: Optimised dual-metal c-MOFs show lower onset overpotential and Tafel slope for OER according to the review's account of the cited work.
Controlling variables: Metal cluster identity · Ni/Zn modulation · Ni-O4 and Ni-N4 site interaction · Projected density of states
Representative materials: NiPc-Ni c-MOF · MPc-M' c-MOFs
Caveat: The review presents this as a transferable design idea but does not establish generality across all electrocatalytic reactions.
290 · 3.1 Water electrolysis · Fig. 5
The review identifies interfacial synthesis and layer-by-layer deposition as established routes for phthalocyanine-based c-MOFs.
Claimed effects: Potentially supports thin-film or layered framework formation for electrochemical use.
Controlling variables: Interface composition · Layer deposition sequence · Film growth conditions
Representative materials: Phthalocyanine-based c-MOF films
Caveat: Only taxonomy-level treatment is given.
287 · 1 Introduction
Porous MOFs can incorporate functional guests after synthesis to promote electron or charge transport.
Claimed effects: Guest-promoted pathways can raise conductivity and extend MOF function in electrochemical contexts.
Controlling variables: Porosity · Guest identity · Spatial proximity of redox components · Post-synthetic processing
Representative materials: Zr-TNDC
Caveat: Example is not phthalocyanine-based; it is used as a conductive-MOF mechanism analogy.
288 · 2 Conductive mechanisms · Fig. 3
The review lists exfoliation as a top-down route to phthalocyanine-based c-MOFs, but does not elaborate recipes because synthesis is outside its main scope.
Claimed effects: Can access layered phthalocyanine c-MOF forms suitable for electrocatalytic study.
Controlling variables: Exfoliation method · Layer retention · Framework integrity
Representative materials: Phthalocyanine-based c-MOFs
Caveat: Mentioned only as a broad class; no process-level extraction should be inferred.
287 · 1 Introduction
These are the review authors’ synthesis, not newly measured results.
NiPc-NiO4 CO2RR performance is attributed to high conductivity, accessible single active sites, significant CO2 adsorption, and in-plane full p-d conjugation.
Evidence basis: single_reference
Caveat: The causal attribution is review-reported and should be checked against the cited primary study for quantitative comparison.
292 · 3.3 CO2 reduction reaction · Fig. 7
Conductivity in MOFs is framed as depending on carrier mobility and carrier concentration, with band-like and hopping transport as the two broad limiting mechanisms.
Evidence basis: single_reference
Caveat: The review imports this framework from broader conductive-MOF literature and applies it to phthalocyanine c-MOFs.
288 · 2 Conductive mechanisms
The outlook argues that conductivity can be improved through morphology control, component manipulation, structural engineering, crystallinity, heterostructures, and conductive-substrate anchoring.
Evidence basis: review_reasoning
Caveat: The review lists strategy classes rather than benchmarking them comparatively.
294 · 4.2 Conductivity
In-plane extended conjugation and layered porosity are interpreted as enabling both mass diffusion and electron or charge transfer, thereby enhancing electrocatalytic activity.
Evidence basis: review_reasoning
Caveat: The review synthesises this as a general mechanism; reaction-specific causality must be checked in primary studies.
286 · Abstract
The review states that HER evidence for phthalocyanine-based c-MOFs is limited, so competing reactions and DFT are sometimes used indirectly to infer HER-related behaviour.
Evidence basis: review_reasoning
Caveat: HER comparisons should not be treated as a mature benchmark set for this family.
289 · 3.1 Water electrolysis · Fig. 4
Assigning band-like versus hopping transport in crystalline MOFs is difficult when grain boundaries and structural defects are substantial.
Evidence basis: review_reasoning
Caveat: This cautions against overinterpreting conductivity mechanisms without crystallographic and transport evidence.
288 · 2 Conductive mechanisms
NiPc-NiN4 c-MOF conductivity is attributed to d-p conjugation between NiN4 nodes and NiPc-substituted o-phenylenediamine, creating electron delocalisation across layers.
Evidence basis: single_reference
Caveat: The extraction preserves this as the review's interpretation of the cited study.
287 · 2 Conductive mechanisms
FePc-pz is presented as a high-performing NRR electrocatalyst because Fe-N4 active sites, porous columnar stacking, and in-plane conjugation jointly favour N2 activation and electron transfer.
Evidence basis: single_reference
Caveat: Benchmark and mechanism are secondary summaries from the review.
293 · 3.4 N2 reduction reaction · Fig. 8
Dual-metal phthalocyanine c-MOFs are presented as an OER design route because metal-cluster interactions tune electronic structure and catalytic descriptors.
Evidence basis: single_reference
Caveat: The review suggests transferability but gives one main cited example.
290 · 3.1 Water electrolysis · Fig. 5
For PcCu-O8-Co, in situ Raman spectra and modelling are reported to identify cobalt nodes as ORR active sites.
Evidence basis: single_reference
Caveat: This is the review's summary of the cited primary study; mechanistic details require the original paper.
291 · 3.2 Oxygen reduction reaction · Fig. 6
Reaction-specific electrolyte and condition preferences must be accounted for when designing phthalocyanine-based c-MOFs for different electrochemical targets.
Evidence basis: review_reasoning
Caveat: The review gives UOR and HER as examples rather than a comprehensive operating-window table.
293 · 3.5 Other possible reactions
Phthalocyanine-based c-MOFs are treated as a distinct layer-stacked conductive MOF subclass that had been relatively overlooked within broader c-MOF electrocatalysis reviews.
Evidence basis: multi_reference
Caveat: The claim reflects the review authors' positioning against prior reviews rather than a quantitative bibliometric analysis.
287 · 1 Introduction
The review highlights inter-site distance as an often overlooked determinant of intermediate diffusion, adsorption, and selectivity.
Evidence basis: review_reasoning
Caveat: This is a design heuristic rather than a cited quantitative rule in the review.
294 · 4.3 Selectivity
Long-term stability is framed as a practical requirement that depends on morphology, composition, size, metal-centre choice, linkages, and oxidation states.
Evidence basis: review_reasoning
Caveat: The review does not provide standardised durability metrics.
294 · 4.4 Stability
Every row remains visibly secondary and links to a primary dossier only where the mapping is verified.
| Material | Property | Reported value | Context and quality | Primary evidence | Review source |
|---|---|---|---|---|---|
| SecondaryFePc-pz | Faradaic efficiency for NRR | 31.9% | NRR at -0.1 V vs RHE. Text · Exact Reported | No verified corpus mapping | 292 · 3.4 N2 reduction reaction · Fig. 8 |
| SecondaryFePc-pz | Ammonia yield rate | 33.6 ug h^-1 mgcat^-1 | NRR at -0.1 V vs RHE. Text · Exact Reported | No verified corpus mapping | 292 · 3.4 N2 reduction reaction · Fig. 8 |
| SecondaryNiPc-NiN4 c-MOFs | Electrical conductivity | 2.39 x 10^-4 S m^-1 | Review-reported conductivity for porous NiPc-NiN4 c-MOFs. Text · Exact Reported | research_0525 | 287 · 2 Conductive mechanisms |
| SecondaryNiPc-NiO4 c-MOF nanosheets | CO production selectivity | nearly 100% | CO2RR; high current density also noted by the review. Text · Approximate | No verified corpus mapping | 292 · 3.3 CO2 reduction reaction · Fig. 7 |
| SecondaryPcCu-O8-Co c-MOF | ORR half-wave potential | 0.83 V vs RHE | ORR half-wave potential; review states it is comparable to commercial Pt/C. Text · Exact Reported | No verified corpus mapping | 291 · 3.2 Oxygen reduction reaction · Fig. 6b |
| SecondaryBulk Zr-TNDC | Electrical conductivity | 7.88 x 10^-5 S m^-1 | Bulk Zr-TNDC under the same test conditions as post-synthetic processed Zr-TNDC. Text · Exact Reported | No verified corpus mapping | 289 · 2 Conductive mechanisms |
| SecondaryPost-synthetic processed Zr-TNDC | Electrical conductivity | 3.16 x 10^-2 S m^-1 | Post-synthetic processed Zr-TNDC under the same test conditions as bulk Zr-TNDC. Text · Exact Reported | No verified corpus mapping | 289 · 2 Conductive mechanisms |
Open questions are presented as review-author priorities, not conclusions from the primary database.
High overpotential, low current density, poor selectivity, and poisoning remain obstacles to highly active electrocatalysts.
Proposed direction: Use DFT and in situ characterisation to identify mechanisms and tune metal nodes or organic ligands to improve adsorption/desorption energetics.
293 · 4.1 Catalytic activity
The regulation mechanism connecting phthalocyanine c-MOF structure to CO2RR activity and selectivity remains insufficiently explored.
Proposed direction: Systematically vary MPc centres and linkages, then connect active-site structure, conductivity, adsorption, and product selectivity.
292 · 3.3 CO2 reduction reaction
Limited conductivity of pristine MOFs remains a significant constraint on highly electroactive MOF development.
Proposed direction: Improve crystallinity, morphology, heterostructures, charge transport pathways, and conductive-substrate anchoring.
294 · 4.2 Conductivity
The review says reports on phthalocyanine-based c-MOFs for HER are too limited to demonstrate HER activity robustly.
Proposed direction: Build a larger set of direct HER studies and avoid relying only on inverse activity from competing reactions or DFT screening.
289 · 3.1 Water electrolysis · Fig. 4
Electrocatalytic selectivity is complicated by competing pathways such as 2-electron versus 4-electron ORR and different CO2RR/NRR products.
Proposed direction: Precisely control active-site structure and inter-site distance to guide intermediate diffusion, adsorption, and product-forming pathways.
294 · 4.3 Selectivity
The review identifies stability as a crucial practical indicator for long-term operation but does not present standardised durability benchmarks.
Proposed direction: Design metal centres and linkages for durable morphology, composition, size, and oxidation-state stability under operating conditions.
294 · 4.4 Stability
Grain boundaries and defects make it difficult to determine whether transport is hopping or band-like in crystalline MOFs.
Proposed direction: Pair conductivity measurements with crystallinity, defect, temperature-dependent, and spectroscopic analysis before assigning mechanisms.
288 · 2 Conductive mechanisms
Mappings show which printed review references have a verified counterpart in the frozen primary corpus.
| Reference | Study | Role and context | Corpus mapping |
|---|---|---|---|
| Ref. 122020 | Title unavailable | transport_framework · conductivity_mechanismsProvides the broader conductive-MOF transport framework adopted for phthalocyanine c-MOFs. | Unmapped |
| Ref. 182018 | Title unavailable | oer_example · bottom_up_synthesisCited as an early NiPc-based c-MOF OER example deposited on FTO. | Unmapped |
| Ref. 192020 | Title unavailable | structure_figure · phthalocyanine_cmof_structureSource for the review's Fig. 1 structural illustration of phthalocyanine c-MOF synthesis and eclipsed stacking. | Unmapped |
| Ref. 202023 | Title unavailable | prior_review · electrocatalysis_contextPrior review cited for broad c-MOF electrocatalysis and electrochemical sensors. | Unmapped |
| Ref. 212021 | Title unavailable | prior_review · device_contextPrior review cited for 2D c-MOFs in multifunctional devices such as FETs, superconductors, chemiresistors, and photodetectors. | research_0061 |
| Ref. 222021 | Title unavailable | prior_review · heterogeneous_electrocatalysis_contextPrior review cited for c-MOFs in heterogeneous electrocatalysis, synthesis, and electrochemical applications. | Unmapped |
| Ref. 282021 | Title unavailable | conductivity_benchmark · material_exampleCited for porous NiPc-NiN4 c-MOF conductivity and d-p conjugation interpretation. | research_0525 |
| Ref. 292020 | Title unavailable | conductivity_benchmark · guest_promoted_transportUsed as a non-phthalocyanine example of post-synthetic guest-promoted conductivity. | Unmapped |
| Ref. 342021 | Title unavailable | nrr_benchmark · her_competition · mpc_pz_materialCited for MPc-pz synthesis, HER/NRR free-energy comparison, and FePc-pz NRR performance. | Unmapped |
| Ref. 352021 | Title unavailable | oer_example · dual_metal_modulationCited for dual-metal cluster modulation of phthalocyanine c-MOF electronic structure and OER activity. | research_0483 |
| Ref. 382019 | Title unavailable | orr_benchmark · in_situ_ramanCited for ORR activity, half-wave potential, and in situ Raman identification of Co active sites in PcCu-O8-Co. | Unmapped |
| Ref. 452020 | Title unavailable | co2rr_example · conductive_nipc_complexCited for a conductive NiPc-based complex for CO2RR with high CO selectivity and current density. | Unmapped |
| Ref. 462021 | Title unavailable | co2rr_benchmark · nipc_nio4_materialCited for NiPc-NiO4 c-MOF nanosheets, nearly quantitative CO selectivity, and structure-property interpretation in CO2RR. | Unmapped |