Hydrogen Evolution Reaction Catalysis Research Articles

Boosting Hydrogen Evolution Reaction on Co9S8 in Neutral Media Leveraging Oxophilic CrOx Mosaic Dopant

AbstractThe electrochemical production of sustainable hydrogen under neutral conditions is advantageous, as it allows for the use of wastewater or seawater without the need for pH adjustments. However, the low ion concentration in neutral electrolytes typically results in limited adsorption of reactants on the catalyst surfaces, leading to sluggish reaction kinetics. Therefore, enhancing absorption capacity is a key challenge in the development of neutral hydrogen evolution reaction (HER) catalysts. Hetero‐structured catalysts may improve surface adsorption through extensive interfacing between phases, enabling active transportation of reaction intermediates. Integrating metal sulfides and oxides, in particular, holds the potential for generating efficient electrocatalysts with improved HER activity and surface adsorption capacity. Herein, the synthesis of CrOx‐doped Co9S8/CuCrS2 mosaic hetero‐nanostructures is reported as a proficient HER catalyst. Facile Cr‐cation migration at the Co9S8/CuCrS2 interface enables the preparation of Cr‐oxide sub‐nano domains within the sulfide matrix, boosting the HER catalysis in neutral media. The exceptional electrochemical performance is demonstrated in a pH 7.4 phosphate buffer solution, including low overpotential, small Tafel slope, and stability over 60 h. The formulation of catalyst design and synthetic approaches has the potential to pave the way for diverse catalytic applications utilizing metal oxide‐doped hetero‐nanostructures.

Mechanically mixing copper and iron at subnanometric scale for catalyzing hydrogen evolution reaction

Mechanically mixing copper and iron at subnanometric scale for catalyzing hydrogen evolution reaction

Role of Surfactants on Electrocatalytic Activity of Co/Al Layered Double Hydroxides For Hydrogen and Oxygen Generation

AbstractLayered double hydroxides (LDHs) have recently attracted much attention in the scientific community as a prominent catalyst for oxygen evolution reaction (OER) because they are economical, extremely stable, and highly active. Literature on LDH alone and their hybrids for catalyzing water oxidation are readily available, but LDH catalyzing hydrogen evolution reaction (HER) is meager. Here, we synthesized Co/Al‐based LDH systems that efficiently perform as bifunctional electrocatalysts for both HER and OER. Exfoliation of this layered material via anion intercalation into a few layers further enhanced its activity. In this work, we reported the synthesis of Co/Al LDHs via coprecipitation followed by hydrothermal method and different surfactant‐functionalized LDHs (with anionic surfactant: SDS, cationic surfactant: CTAB, and nonionic surfactant: PEG 4000). SDS‐modified LDH (s LDH) showed notable stability and competent results in hydrogen evolution in addition to oxygen evolution. The exfoliation of s LDH caused enhancement in the high specific surface area about 6.8 times compared to pristine LDH, as evident from BET data. The onset potential for HER as obtained from the polarization curve for s LDH is −0.41 V versus RHE, with Tafel slope of 67.4 mV/dec. Similarly, OER onset potential and corresponding Tafel slope are 1.53 V versus RHE at 10 mA/cm2 and 90.2 mV/dec, respectively.

Layered high-entropy sulfides: boosting electrocatalytic performance for hydrogen evolution reaction by cocktail effects

Abstract This study explores high-entropy sulfides (HESs) as potential electrocatalysts for the hydrogen evolution reaction (HER). Novel Pa-3 and Pnma structured HESs containing Fe, Mn, Ni, Co and Mo, were synthesized via a facile mechanochemical method. Structural and chemical properties were extensively characterized using x-ray diffraction, transmission electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The electrocatalytic performance of four as-prepared HESs in alkaline electrolyte for HER reveals the remarkable outperformance compared to medium-entropy and conventional sulfides. Particularly, (Fe0.2Mn0.2Ni0.2Co0.2Mo0.2)S2 demonstrated outstanding activities, with minimal overpotentials (187 mV at 10 mA cm–2) and outstanding durability under harsh alkaline conditions (a mere polarization increase ΔE = 17 mV after 14 h via chronopotentiometry). The remarkable catalytic activities can be attributed to synergistic effects resulting from the cocktail effects within the high-entropy disulfide. The introduction of Mo contributes to the formation of a layered structure, which leads to an increased surface area and thus to a superior HER performance compared to other HES and conventional sulfides. This work demonstrates the promising potential of HES and underscores that further development for catalytic applications paves the way for innovative routes to new and more efficient active materials for HER catalysis.

Interfacial engineering of core/satellite-structured RuP/RuP2 heterojunctions for enhancing pH-universal hydrogen evolution reaction

Developing renewable hydrogen technologies requires high-efficiency pH-universal hydrogen evolution reaction (HER) electrocatalysts. Ruthenium phosphides (RuPx) have great potentials to replace the commercial Pt-based materials, whereas the optimization of their electronic structure for favorable reaction intermediate adsorption remains a significant challenge. Herein, we report an innovative phosphorization-controlled strategy for the in-situ immobilization of core/satellite-structured RuP/RuP2 heteronanoparticles onto N, P co-doped porous carbon nanosheets (abbreviated as RuP/RuP2@N/P-CNSs hereafter). Density functional theory (DFT) calculations further reveal that the electron shuttling at the RuP/RuP2 interface leads to a reduced energy barrier for H2O dissociation by electron-deficient Ru atoms in the RuP and the optimized H∗ adsorption of electron-gaining Ru atoms in the RuP2. Impressively, the as-synthesized RuP/RuP2@N/P-CNSs exhibits low overpotentials of 8, 29, and 66 mV to achieve 10 mA cm−2 in alkaline, acid and neutral media electrolyte, respectively. This research presents a viable approach to synthesize high-efficiency transition metal phosphide-based electrocatalysts and offers a deeper comprehension of interface effects for HER catalysis.

Hydrogen Evolution Catalysis by Cobalt Complexes of an Aza‐Bridged Bis‐1,10‐Phenanthroline Ligand Bearing Pendant Basic Sites

AbstractA novel series of molecular Co(II) complexes with aza‐bridged bis‐1,10‐phenanthroline (bpa) ligands have been synthesized and reported for the catalytic hydrogen evolution reaction (HER). Various nitrogen donor substituents are introduced at the aza‐bridge of the bis‐phenanthroline moieties render intramolecular basic sites in the complexes’ second‐coordination sphere. Modifying the pendant nitrogen donor significantly influences the catalytic HER performance. Among these, the cobalt complex with the (2‐pyridyl)methyl substituted bis‐phenanthroline ligand (L3) exhibits the most photocatalytic HER efficiency in both organic and aqueous media. Under optimized conditions with [Ru(bpy)3]2+ as a sensitizer and ascorbic acid as an electron donor, [CoII(L3)(TfO−)2] achieves an initial turnover frequency (TOF) of 1882±65 h−1 per catalyst and a turnover number (TON) of 4842±122 in a 3 hour reaction period under the irradiation of visible light. Combined experimental and theoretical evidences illustrate that phenanthroline moieties of the bpa ligands act as electron mediators during the HER catalysis, while the pendant nitrogen donor substituents mediate proton transfer. This work provides a unique example for understanding the activity‐structure relationship of homogeneous HER catalyst concerning the redox‐active properties and second coordination sphere basic sites of organic ligand platforms.

Chronopotentiometric Stripping Analysis of Proteins and Their Interactions

Chronopotentiometric constant current stripping analysis (CPS) is a highly sensitive method for protein analysis that does not require modification or labeling. During the CPS analysis, proteins yield the so-called peak H, resulting from the catalytic hydrogen evolution reaction. This peak is sensitive to both local and global changes in protein structure, allowing the study of individual proteins, as well as their complexes. CPS analysis has been utilized in studying biomedically important proteins involved in neurodegenerative diseases and cancer. In this article, we describe the development of CPS protein analysis and its progress over the past decade. We also demonstrate the versatility of the method and its potential applications.

Factorial Optimization of CoCuFe-LDH/Graphene Ternary Composites as Electrocatalysts for Water Splitting.

The layered double hydroxides (LDHs) have demonstrated significant potential as non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Their unique compositional and structural properties contribute to their efficiency and stability as catalysts. In this study, CoCuFe-LDH composites were grown on graphene (G) via a cost-effective and straightforward one-step hydrothermal process. A 2-level full-factorial model was employed to determine the impact of Co (1.5, 3, and 4.5 mmol) and graphene (10, 30, and 50 mg) concentrations on the onset potential of OER and HER, which were the chosen response variables. OER and HER activity variabilities were assessed in triplicate using Co[3]Cu[3]Fe[3]-LDH/G[30] (central point), which were determined at 0.01% and 0.02%, respectively. Statistical analyses demonstrated that Co[4.5]Cu[3]Fe[3]-LDH/G[10] and Co[1.5]Cu[3]Fe[3]-LDH/G[10] showed the lowest onset potential at 1.52 V and -0.32 V (V vs RHE) for the OER and HER, respectively, suggesting that a high cobalt concentration enhances OER performance, while optimal HER catalysis was achieved with lower cobalt concentrations. Moreover, the trimetallic composites exhibited good stability with negligible loss of catalytic activity over 24 h.

Simultaneous Defect Passivation and Co‐Catalyst Engineering Leads to Superior Photocatalytic Hydrogen Evolution on Metal Halide Perovskites

AbstractMetal halide perovskites (MHPs) have emerged as attractive candidates for producing green hydrogen via photocatalytic pathway. However, the presence of abundant defects and absence of efficient hydrogen evolution reaction (HER) active sites on MHPs seriously limit the solar‐to‐chemical (STC) conversion efficiency. Herein, to address this issue, we present a bi‐functionalization strategy through decorating MHPs with a molecular molybdenum‐sulfur‐containing co‐catalyst precursor. By virtue of the strong chemical interaction between lead and sulfur and the good dispersion of the molecular co‐catalyst precursor in the deposition solution, a uniform and intimate decoration of the MHPs surface with lead sulfide (PbS) and amorphous molybdenum sulfide (MoSx) co‐catalysts is obtained simultaneously. We show that the PbS co‐catalyst can effectively passivate the Pb‐related defects on the MHPs surface, thus retarding the charge recombination and promoting the charge transfer efficiency significantly. The amorphous MoSx co‐catalyst further promotes the extraction of photogenerated electrons from MHPs and facilitates the HER catalysis. Consequently, drastically enhanced photocatalytic HER activities are obtained on representative MHPs through the synergistic functionalization of PbS and MoSx co‐catalysts. A solar‐to‐chemical (STC) conversion efficiency of ca. 4.63 % is achieved on the bi‐functionalized FAPbBr3‐xIx (FA=CH(NH2)2), which is among the highest values reported for MHPs.

Simultaneous Defect Passivation and Co-Catalyst Engineering Leads to Superior Photocatalytic Hydrogen Evolution on Metal Halide Perovskites.

Metal halide perovskites (MHPs) have emerged as attractive candidates for producing green hydrogen via photocatalytic pathway. However, the presence of abundant defects and absence of efficient hydrogen evolution reaction (HER) active sites on MHPs seriously limit the solar-to-chemical (STC) conversion efficiency. Herein, to address this issue, we present a bi-functionalization strategy through decorating MHPs with a molecular molybdenum-sulfur-containing co-catalyst precursor. By virtue of the strong chemical interaction between lead and sulfur and the good dispersion of the molecular co-catalyst precursor in the deposition solution, a uniform and intimate decoration of the MHPs surface with lead sulfide (PbS) and amorphous molybdenum sulfide (MoSx) co-catalysts is obtained simultaneously. We show that the PbS co-catalyst can effectively passivate the Pb-related defects on the MHPs surface, thus retarding the charge recombination and promoting the charge transfer efficiency significantly. The amorphous MoSx co-catalyst further promotes the extraction of photogenerated electrons from MHPs and facilitates the HER catalysis. Consequently, drastically enhanced photocatalytic HER activities are obtained on representative MHPs through the synergistic functionalization of PbS and MoSx co-catalysts. A solar-to-chemical (STC) conversion efficiency of ca. 4.63 % is achieved on the bi-functionalized FAPbBr3-xIx (FA=CH(NH2)2), which is among the highest values reported for MHPs.

Nanocarbons-Based Trifunctional Electrocatalysts for Overall Water Splitting and Metal-Air Batteries: Metal-Free and Hybrid Electrocatalysts.

Trifunctional electrocatalysts, an exciting class of materials that can simultaneously catalyze hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR), can significantly enhance the performance and economic viability of electrochemical energy storage and conversion technologies such as water-splitting electrolyzers, metal-air batteries, fuel cells and their integrated devices. Such multifunctional electrocatalysts encompass multiple active sites that can simultaneously catalyze two or more different electrochemical reactions and are feasible routes for addressing global energy and environmental challenges. This review accounts for nanocarbons-based trifunctional electrocatalysts reported for electrolyzers, metal-air batteries and integrated electrolyzer-battery systems, providing a practical perspective. Metal-free and hybrid (hybrids of nanocarbons and transition metals/compounds) trifunctional electrocatalysts are covered. Given the growing importance of green technologies, we discuss biomass-derived carbon-based trifunctional electrocatalysts separately. The collective information provided in the review could help researchers derive more effective and durable trifunctional electrocatalysts suitable for commercial use.

High performance Sm substituted Ni-Zn catalysts for green hydrogen generation via Photo/Electro catalytic water splitting processes

In this work, samarium doped Ni-Zn catalysts with a composition of Ni0.9Zn0.1SmyFe2-yO4 (y = 0–0.03) are made by inorganic sol–gel auto-combustion (SC) route. These Ni-Zn materials depict the forming of typical cubic crystal structure (Fd3m) and it is affirmed by the X-ray diffraction plots. The existence of cubic, spherical, and aggregated shaped grains with an average grain size that falls in between the range of 188 to 316 nm are confirmed from the FESEM images of prepared materials. According to the photo catalytic water splitting research findings, the total hydrogen yield for the Ni-Zn1, Ni-Zn2, Ni-Zn3, and Ni-Zn4 catalysts after four hours are 16.17, 15.02, 23.47 and 24.99 mmol gcat-1. Among all the compositions, the Ni-Zn4 photocatalyst exhibits the maximum photocatalytic performance of 24.99 mmol gcat-1. However, the Ni-Zn4 sample also shows the high electro catalytic hydrogen evolution reaction (HER) performance. With their outstanding photo/electro performance, the synthesized Sm-doped Ni-Zn nanoferrites shows great promise as potential candidates for the green hydrogen generation.

Facile preparation of PtNi/Cs derived from the precipitation polymerization of a Poly(amic acid) for efficient hydrogen evolution reaction catalysis

Hydrogen evolution reaction (HER) of water is currently one of the most potential ‘green hydrogen’ production technology to alleviate the energy scarcity and environmental contamination. In this study, ultrafine platinum/nickel bimetallic nanoparticles loaded porous carbon nanocomposite, noted as PtNi/Cs, is facilely prepared by employing the precipitation polymerization of a poly (amic acid) (PAA), which shows superior catalytic performance toward HER. The synthesis of PAA is achieved via a stepwise polymerization of 4,6-diaminino-2-mercaptopyrimidine and pyromellitic dianhydride at room temperature, and the porous precursor is formed during the polymerization. Upon pyrolysis of the precursor in an inert atmosphere, carbon nanoaggregates with inherited porosity are fabricated. Ultrafine PtNi bimetallic nanoparticles with size of 3.3 ± 0.7 nm can be efficiently deposited, exhibiting an overpotential of 26.4 mV at 10 mA cm−2 and a mass activity of 2.92 A mgPt−1, superior than commercial Pt/C of 36.8 mV. The excellent HER performance can be attributed to the formation of ultrafine PtNi bimetallic nanoparticles and the electron transfer from PtNi to the nitrogen atoms on the carbon support.

Pt nanoparticles loaded on three-dimensional porous carbon as electrocatalysts for hydrogen evolution reaction

The electrochemical catalytic hydrogen evolution reaction (HER) holds significant potential for the sustainable production of environmentally friendly hydrogen energy. Currently, the precious metal Pt is widely acknowledged as the most superior electrocatalyst. However, its limited availability and exorbitant cost impede its extensive application. In this study, low Pt-loaded three-dimensional (3D) porous carbon composites were successfully synthesized as catalysts using a template-free method and a high-temperature pyrolysis method. By evaluating the HER performance of different Pt concentrations of the catalysts Pt/C-X (X=0, 0.05, 0.1, 0.2, 0.4, 0.7 mmol) in acid solution, it was observed that the overpotential of Pt/C-0.2 reached as low as 17 mV with a significantly low Tafel slope value of 48 mV cm−2. Meanwhile, the Bilayer capacitance (Cdl) reached an impressively high value of 247.5 mF cm−2. Consequently, this also provides a promising way to enhance the catalytic performance of the loaded catalysts.

WOx-Carbon nanorods catalyzed photoelectrochemical hydrogen evolution reaction of silicon-photocathode in acidic media

Silicon (Si) photocathode with surface decoration of co-catalysts is a promising material for green hydrogen production. The surface of the Si is often further etched into pyramids for optical absorption. However, the photon-generated charges tend to concentrate on the pyramid peaks, whilst the catalyst of nanoparticles generally aggregate in the valley, where less charges are available. In this work, one-dimensional tungsten oxide (WOx) with an ultra-thin layer of carbon species have been used as the cocatalyst, which preferentially stay on the upperpart of the pyramids with intimate contact. WOx has great potential in catalysis for hydrogen evolution reaction (HER) due to its ideal proton adsorption/desorption behavior. However, WOx, especially in form of nanorods, has rarely been reported as cocatalysts for photo(electro)catalysis, due to the challenges in the preparation and stabilities during long-term HER catalysis. Herein, the formation of WOx-C nanorods was induced, leading to improved conductivity and stability as co-catalysts. The density functional theory (DFT) calculations revealed the low reaction free energy of WOx-C co-catalysts and the smooth electrons transfer from W to protons. The Si photocathodes deposited with the optimized WOx-C hybrids nanorods showed high performance in PEC reaction, achieving a current density of −21.3 mA·cm−2 at 0 VRHE and an onset potential of +0.218 VRHE under acidic conditions. The catalytic mechanism of WOx-C nanorods for the pyramidal Si-photocathode is investigated and proposed.

Fe2N5P dual-atom catalysts: A pathway to efficient hydrogen evolution in renewable energy applications

Dual-atom catalysts (DACs) are expected to improve the catalytic activity compared to single-atom catalysts (SACs). This improvement is attributed to the synergistic interaction between adjacent bimetallic atoms in DACs. Recently, the highly active Fe2N5P sites embedded in covalent organic framework-derived carbon have been demonstrated to catalyze oxygen reduction reaction (doi:10.1021/acscatal.3c02186). Motivated by this fascinating finding of Fe2N5P-based DACs, their potential for catalyzing hydrogen evolution reaction (HER) has been investigated. Thus, electrocatalytic activities of the Fe2N6 and Fe2N5P-based DACs embedded in graphene layer were systematically investigated toward the HER. Our results show that the Fe2N6 site embedded in graphene shows high catalytic activity and selectivity toward the HER. However, our results reveal that the P atom in the Fe2N5P dual-site facilitates the × H formation and thus improves its catalytic activity toward HER due to a greater degree of synergistic effect. The computed Gibbs free energies confirm the higher feasibility of HER on the Fe center of Fe2N5P compared to the Fe2N6 DAC.

High-Density Dual-Structure Single-Atom Pt Electrocatalyst for Efficient Hydrogen Evolution and Multimodal Sensing.

Herein, we report a high-density dual-structure single-atom catalyst (SAC) by creating a large number of vacancies of O and Ti in two-dimensional (2D) Ti3C2 to immobilize Pt atoms (SA Pt-Ti3C2). The SA Pt-Ti3C2 showed excellent performance toward the pH-universal electrochemical hydrogen evolution reaction (HER) and multimodal sensing. For HER catalysis, compared to the commercial 20 wt % Pt/C, the Pt mass activities of SA Pt-Ti3C2 at the overpotentials of ∼30 and 110 mV in acid and alkaline media are 45 and 34 times higher, respectively. More importantly, during the alkaline HER process, an interesting synergetic effect between Pt-C and Pt-Ti sites that dominated the Volmer and Heyrovsky steps, respectively, was revealed. Moreover, the SA Pt-Ti3C2 catalyst exhibited high sensitivity (0.62-2.65 μA μM-1) and fast response properties for the multimodal identifications of ascorbic acid, dopamine, uric acid, and nitric oxide under the assistance of machine learning.

Strong Interaction between Molybdenum Compounds and Mesoporous CMK‐5 Supports Boosts Hydrogen Evolution Reaction

AbstractStrong metal‐support interaction (SMSI) between transition metal nanoparticles and carbon matrix offers significant structure advantages due to the ability to modulate the electronic structure of metal nanoparticles, increase the density of active sites, and improve the conductivity of catalysts. Here, ultrafine nanoparticles of metallic molybdenum compounds (MoP, Mo2C, and MoS2) strongly coupled with mesoporous carbon CMK‐5 are synthesized. The confinement growth of nanoparticles in the pores of CMK‐5 produces encapsulated nanoparticles, affording facilitated electron transfer, and enhancing the HER activity induced by the SMSI effect. The hierarchical nanostructure and strong electronic interactions between the carbon substrate and molybdenum‐based nanoparticles allow efficient mass/electron transport between the carbon substrate and molybdenum‐based nanoparticles, improving the catalytic hydrogen evolution reaction (HER) activity. The effective electron exchange between the Mo species and the CMK‐5 support is studied by X‐ray photoelectron spectroscopy (XPS) measurement, confirming the presence of the SMSI effect. The resulting MoP/CMK‐5 catalyst exhibits outstanding HER performance in alkaline (65 mV@10 mA cm−2), acidic (123 mV@10 mA cm−2), and simulated seawater electrolytes (103 mV@10 mA cm−2), making it one of the most promising catalysts reported for HER. This work provides guidance on designing high‐performance electrocatalysts with SMSI for the enhancement of the electrochemical reaction.

Prediction of the catalytic mechanism of hydrogen evolution reaction enhanced by surface oxidation on FCC_CoCrFeNi and Co0.35Cr0.15Fe0.2Mo0.1Ni0.2 multi-principal element alloys based on site preference

Some multi-principal element alloy (MPEA) catalysts may exhibit the ability to promote the hydrogen evolution reaction (HER) and maintain stability under acidic conditions. Here, we investigated the impact of ordered behavior and surface oxidation of FCC_CoCrFeNi and Co0.35Cr0.15Fe0.2Mo0.1Ni0.2 MPEAs on HER performance through first-principles calculations. The ordering behaviors of MPEAs were described using L12_AuCu3 sublattice model and the predicted site occupying fractions (SOFs). And we found that the catalytic activity of single intermediate *H at top or bridge adsorption sites surpassed that at the hollow site. However, the hollow site exhibits strong adsorption towards *H, resulting in the transfer of *H from other sites to hollow site. Meanwhile, compared to those containing only hydrogen, MPEAs with both hydrogen and oxygen exhibit lower overpotentials, primarily due to oxygen facilitating hydrogen adsorption and subsequent desorption from MPEA surfaces, thus, such fundamental finding highlights the beneficial role of alloy surface oxidation in promoting HER performance. Furthermore, the overpotential values of the three slab models based on SOFs are similar, demonstrating considerably consistent atomic distribution behaviors, thereby better reflecting the overall catalytic performance of ordered MPEAs. These explorations bring new insights into the ordered behavior and surface oxidation of MPEAs in HER catalysis.

Covalent versus noncovalent attachments of [FeFe]‑hydrogenase models onto carbon nanotubes for aqueous hydrogen evolution reaction

In an effort to develop the biomimetic chemistry of [FeFe]‑hydrogenases for catalytic hydrogen evolution reaction (HER) in aqueous environment, we herein report the integrations of diiron dithiolate complexes into carbon nanotubes (CNTs) through three different strategies and compare the electrochemical HER performances of the as-resulted 2Fe2S/CNT hybrids in neutral aqueous medium. That is, three new diiron dithiolate complexes [{(μ-SCH2)2N(C6H4CH2C(O)R)}Fe2(CO)6] (R = N-oxylphthalimide (1), NHCH2pyrene (2), and NHCH2Ph (3)) were prepared and could be further grafted covalently to CNTs via an amide bond (this 2Fe2S/CNT hybrid is labeled as H1) as well as immobilized noncovalently to CNTs via π-π stacking interaction (H2) or via simple physisorption (H3). Meanwhile, the molecular structures of 1–3 are determined by elemental analysis and spectroscopic as well as crystallographic techniques, whereas the structures and morphologies of H1-H3 are characterized by various spectroscopies and scanning electronic microscopy. Further, the electrocatalytic HER activity trend of H1 > H2 ≈ H3 is observed in 0.1 M phosphate buffer solution (pH = 7) through different electrochemical measurements, whereas the degradation processes of H1-H3 lead to their electrocatalytic deactivation in the long-term electrolysis as proposed by post operando analysis. Thus, this work is significant to extend the potential application of carbon electrode materials engineered with diiron molecular complexes as heterogeneous HER electrocatalysts for water splitting to hydrogen.