Hydrogen Evolution Reaction In Alkaline Media Research Articles

Highly Active W2C-Based Composites for the HER in Alkaline Solution: the Role of Surface Oxide Species.

The hydrogen evolution reaction (HER) is a crucial electrochemical process for the proposed hydrogen economy since it has the potential to provide pure hydrogen for fuel cells. Nowadays, hydrogen electroproduction is considerably expensive, so promoting the development of new non-noble catalysts for the cathode of alkaline electrolyzers appears as a suitable way to reduce the costs of this technology. In this sense, a series of tungsten-based carbide materials have been synthesized by the urea-glass route as candidates to improve the HER in alkaline media. Moreover, two different pyridinium-based ionic liquids were employed to modify the surface of the carbide grains and control the amount and nature of their surface species. The main results indicate that the catalyst surface composition is modified in the hybrid materials, which are then distinguished by the appearance of tungsten suboxide structures. This implies the action of ionic liquids as reducing agents. Consequently, differential electrochemical mass spectrometry (DEMS) is used to precisely determine the onset potentials and rate-determining steps (RDS) for the HER in alkaline media. Remarkably, the modified surfaces show high catalytic performance (overpotentials between 45 and 60 mV) and RDS changes from Heyrovsky-Volmer to Heyrovsky as the surface oxide structures get reduced. H2O molecule reduction is then faster at tungsten suboxide, which allows the formation of the adsorbed hydrogen at the surface, boosting the catalytic activity and the kinetics of the alkaline HER.

Nickel nanoparticles supported on doped graphene-based materials for the ORR and HER in alkaline medium

In this work, Ni nanoparticles (NPs), with nominal metallic loading of 20 wt%, were deposited on graphene-based materials (GMs) doped with nitrogen and sulphur, in order to study their electrocatalytic activity towards the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) in alkaline medium. Different chemical reducing agents were employed to synthesize the catalysts. Results indicate that the presence of heteroatoms in the GMs influences the activity of both the GMs and the Ni-based catalysts. Thus, best results were obtained for catalyst containing nitrogen and sulphur for the ORR which favours the direct four-electron pathway, whereas for the HER, the highest performance was observed for N-doped materials.

Manganese-cobalt hydroxide nanosheets anchored on a hollow sulfur-doped bimetallic MOF for high-performance supercapacitors and the hydrogen evolution reaction in alkaline media.

Nonmetallic doping and in situ growth techniques for designing electrode materials with excellent electrocatalytic activity are effective strategies to enhance the electrochemical performance. Bifunctional electrode materials for supercapacitors (SCs) and the hydrogen evolution reaction (HER) have attracted great interest due to their potential applications in green energy storage and conversion. Herein, the bimetallic MnCo LDH is anchored on a hollow sulfur (S)-doped MnCo-MOF-74 surface, forming a poplar flower-like 3D composite which is used for SCs and the HER in alkaline media. The fabricated S-MnCo-MOF-74@MnCo LDH/NF electrode exhibits a favorable specific capacitance of 1875.4 F g-1 at 1 A g-1 and steady long-term cycling performance. Moreover, the assembled HSC using S-MnCo-MOF-7@MnCo LDH/NF as the cathode material and active carbon (AC) as the anode material shows 546.4 F g-1 capacitance (1 A g-1) with a maximum energy density of 58 W h kg-1 at 14 000 W kg-1 power density. As an electrocatalyst, S-MnCo-MOF-7@MnCo LDH/NF exhibits excellent HER properties with a small Tafel slope of 128.9 mV dec-1 a low overpotential of 197 mV at 10 mA cm-2 and durable performance for 10 hours in alkaline media. The present work provides insights into understanding and designing active electrode materials for stable hydrogen evolution and high-performing supercapacitors in an alkaline environment.

Effect of Electrochemical Surface Oxidation on Intrinsic Activity Towards the Hydrogen Evolution Reaction of Ultra-Smooth Nanocrystalline Ni Thin Films

Green hydrogen has emerged as a leading contender in the pursuit of a sustainable energy transition, driving the need for optimized catalysts in hydrogen production. Therefore, considerable effort is taken to replace the highly active, yet expensive Pt-group metals with non-noble alternatives such as Ni. Understanding the hydrogen evolution reaction (HER) mechanism on well-performing Ni surfaces is essential for gaining fundamental knowledge and implementing this in practical applications. While high surface area structures are typically designed for enhanced efficiency, there is limited research available on the fundamental aspects of thin films and smooth surfaces, which are crucial for benchmarking intrinsic catalytic activity and elucidating catalytic mechanisms. To address this gap, we perform a combined microstructural and electrochemical evaluation of smooth Ni thin film electrodes to analyze HER in alkaline media.This study aimed to evaluate the intrinsic catalytic properties of nanocrystalline Ni thin films and the effect of electrochemical oxidation on the catalytic behavior, while precisely monitoring the evolution of the film surface state and roughness. In addition to experimental work, Density Functional Theory (DFT) calculations and Kinetic Monte Carlo (KMC) simulations are used to understand HER on oxide-modified Ni surfaces and the role of different elementary processes involved in the HER mechanism.Nanocrystalline low-roughness Ni electrodes for HER were produced via magnetron sputter deposition to minimize the difference between geometrical and electrochemical surface area. This means we find intrinsic material properties directly, bypassing the need for additional measurements for real surface area determination. The analysis of catalyst activities towards HER as well as the oxidation process [1] was performed via cyclic voltammetry, using a three-electrode setup. Within the conducted studies, we can report a significant lowering of the overpotential for HER upon in-situ oxidation of the electrodes due to the existence of NiO, and Ni(OH)2 on the Ni catalyst surface [2], leading also to a limitation of the deactivation processes. Further analysis including topography evaluation (AFM), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) in combination with selected area diffraction (SAED) of the as-deposited and oxidized electrodes confirmed that the observed effect can be assigned to the availability of oxides on the surface assuredly (Figure 1). Additionally, theoretical calculations and simulations (DFT, KMC) support the experimental data and derived theories.In conclusion, the beneficial effect of NiO and Ni(OH)2 presence on Ni surfaces was examined and successfully proven by a combination of electrochemical measurements, material characterization, theoretical calculations, and a careful experimental design that minimizes the influence of interfering factors, such as surface roughness.

An In Situ Fabricated Hydrogel Polymer - Palladium Nanocomposite Electrocatalyst for the HER: Critical Role of the Polymer in Realizing High Efficiency and Stability.

Development of general and simple designs of catalytic electrodes for the hydrogen evolution reaction (HER) is critical. The present work demonstrates the multiple roles played by a hydrogel polymer in the fabrication and activity enhancement of the nanoelectrocatalyst. A nanocomposite thin film of Pd with the insulating hydrogel, poly(2-hydroxyethyl methacrylate) (PHEMA), is fabricated through a facile in situ process, the polymer itself functioning as the reducing/stabilizing agent in the formation of Pd nanoparticles. Pd-PHEMA on Ni foam enables efficient HER in alkaline medium with a low overpotential; the polymer enables the electrocatalysis by its swelling and confinement of the electrolyte. Most significantly, when the electrode is subjected to an optimized cycling protocol, the overpotential decreases steadily, reaching an impressively low value of 36 mV (@10 mA cm-2 ). A low Tafel slope (68 mV dec-1 ), high exchange current density, Faradaic efficiency and TOF (3.27 mA cm-2 , 99 %, 122.7 h-1 ), and extended stability are achieved. Detailed investigations reveal the active role of the polymer in the evolution of the nanocatalyst, itself undergoing favorable morphological changes. The study illustrates the widened scope for developing efficient and stable catalytic electrodes with hydrogel polymers and unique features that promote the generation of green hydrogen.

Recent Tendency on Transition-Metal Phosphide Electrocatalysts for the Hydrogen Evolution Reaction in Alkaline Media.

Hydrogen energy is regarded as an auspicious future substitute to replace fossil fuels, due to its environmentally friendly characteristics and high energy density. In the pursuit of clean hydrogen production, there has been a significant focus on the advancement of effective electrocatalysts for the process of water splitting. Although noble metals like Pt, Ru, Pd and Ir are superb electrocatalysts for the hydrogen evolution reaction (HER), they have limitations for large-scale applications, mainly high cost and low abundance. As a result, non-precious transition metals have emerged as promising candidates to replace their more expensive counterparts in various applications. This review focuses on recently developed transition metal phosphides (TMPs) electrocatalysts for the HER in alkaline media due to the cooperative effect between the phosphorus and transition metals. Finally, we discuss the challenges of TMPs for HER.

Synergistic Integration of MXene and Metal-Organic Frameworks for Enhanced Electrocatalytic Hydrogen Evolution in an Alkaline Environment

The development of transition metal (TM) catalysts to replace precious metals has garnered increasing interest. Specifically, platinum (Pt)-based catalysts have been extensively investigated for their electrochemical performance in hydrogen evolution reaction (HER), which offer a clean means of producing hydrogen fuel without carbon emissions. However, the reliance on Pt-based catalysts has hindered the progress of HER development. Therefore, researchers have explored metal-organic frameworks (MOFs) as a substitute for noble Pt-based catalysts to address this issue. Nevertheless, the low electroconductivity of pure MOFs restricts their application in electrochemical fields. To overcome this limitation, MXenes have emerged as a promising two-dimensional (2D) material for coupling with MOFs to create an electrocatalyst with high electrical conductivity, a large surface area, and a tunable structure. In this study, we report the synthesis of a Ti3C2Tx (MXene) nanosheet-encapsulated MOFs catalyst (Ti3C2Tx@ZIF-8) with high activity and a low cost by encapsulating the precursor with ZIF-8 for HER in alkaline media. The catalyst exhibits an overpotential of only 507 mV at 20 mA/cm2 and a low Tafel slope value of 77 mV/dec. Additionally, cyclic voltammetry (CV) indicates an electrochemical active surface area (ECSA) of 122.5 cm2, and chronopotentiometry demonstrates the stable nature of the catalyst over 20 h without any significant changes in the overpotential value. The excellent electrochemical properties of Ti3C2Tx@ZIF-8 suggest its potential as a promising material for energy conversion applications.

Cu-doped Heterointerfaced Ru/RuSe2 nanosheets with optimized H and H2 O adsorption boost hydrogen evolution catalysis.

Ruthenium chalcogenide is a highly promising catalytic system as a Pt alternative for hydrogen evolution reaction (HER). However, well-studied ruthenium selenide (RuSe2 ) still exhibits sluggish HER kinetics in alkaline media due to the inappropriate adsorption strength of H and H2 O. Herein, w e report a new design of Cu-doped Ru/RuSe2 heterogeneous nanosheets (NSs) with optimized H and H2 O adsorption strength for highly efficient HER catalysis in alkaline media. Theoretical calculations reveal that the superior HER performance is attributed to a synergistic effect of the unique heterogeneous interface structure and Cu doping, which not only optimizes the electronic structure with a suitable d-band center to suppress proton overbinding but also alleviates the energy barrier with enhanced H2 O adsorption. As a result, Cu-doped heterogeneous Ru/RuSe2 NSs exhibit a small overpotential of 23mV at 10mA cm-2 , a low Tafel slope of 58.5mV dec-1 and a high turnover frequency (TOF) value of 0.88 s-1 at 100mV for HER in alkaline media, which is among the best catalysts in noble metal-based electrocatalysts toward HER. The present Cu-doped Ru/RuSe2 NSs interface catalyst is very stable for HER by showing no activity decay after 5000-cycle potential sweeps. This work heralds that heterogeneous interface modulation opens up a new strategy for the designing of more efficient electrocatalysts. This article is protected by copyright. All rights reserved.

Cationic defects coupled with trace Pt under the assistance of corrosive engineering for efficient hydrogen electrocatalysis with large current density

Exploiting efficient and durable samples toward electrocatalytic hydrogen evolution reaction (HER) with large current density is critical for commercializing hydrogen energy. Herein, Ni, Fe layered double hydroxide with cationic defects and trace Pt (Pt/D-NiFe LDH) on NiFe foam is constructed under the assistance of corrosion engineering and alkaline etching at ambient conditions. The porous nanostructure, leaf-like morphology and coexistence of defects and Pt endow the as-designed sample presents a remarkable electrocatalytic activity for HER in alkaline media with low overpotentials with 28, 163 and 217 mV to drive 10, 500 and 1000 mA cm−2. Remarkably, the catalyst enables the two-electrode electrolyzer with low voltages 1.65 and 1.72 V to attain 500 and 1000 mA cm−2. It also can be powered by solar, thermal and wind sustainable energies. The as-synthesized Pt/D-NiFe LDH has excellent catalytic activities and stability in alkaline seawater and neutral electrolytes with small overpotentials.

Nd-Gd–Platinum doped TiO2 nanotube arrays catalyst for water splitting in Alkaline Medium

The utilization of a highly efficient electrocatalyst for the hydrogen evolution reaction (HER) plays an important role in energy conversion in regard to the development of hydrogen-based clean energy sources. The HER in alkaline media by co-doped lanthanide-platinum TiO2 Nanotube Arrays (TNTA) catalyst electrodes has yet to be studied. Here, we report the robust fabrication of an electrocatalyst and its prominent performance in catalyzing the HER. The catalyst electrode consisted of TiO2 nanotube arrays doped with rare earth metals (neodymium (Nd) and gadolinium (Gd)) and a small loading of Pt metal as double-layer nanotube arrays. This material was obtained by a two-step electrochemical anodization method using a small amount of fluoride salt and a short time of mechanical growth. Additionally, an in situ doping strategy that utilized a hydrothermal treatment for the ternary and quaternary ions of Nd, Gd and Pt was performed, while retaining the anatase phase. The Nd-Gd-TNTA catalyst electrode produced a current density of −47.522 µA cm−2 and exhibited a low activation energy of approximately 2.15 kJ/mol. The Nd-Gd-Pt-TNTA catalyst electrode is the best candidate for supporting the HER and advancing water splitting techniques for high-purity hydrogen production in alkaline media.

Insights into the Origin of High Activity of Ni5P4(0001) for Hydrogen Evolution Reaction.

Hydrogen evolution reaction (HER) is directly relevant to green hydrogen production from water splitting. Recently, a low-cost Ni5P4 material has been demonstrated experimentally and theoretically to exhibit excellent electrocatalytic activity toward HER. However, a fundamental understanding of the origin of Ni5P4(0001) activity is still lacking. In this work, density functional theory (DFT) calculations were employed for a comprehensive investigation. The calculation results indicate that the Ni5P4(0001) surface exposing Ni3P4 termination gains the highest stability, on which a nearly thermoneutral hydrogen adsorption was found at the P3-hollow sites, providing a high activity for HER. The activity was also observed to be maintained over a wide H-coverage. HER occurs via the Volmer-Heyrovsky mechanism as evidenced from the optimal hydrogen adsorption free energy, but unlikely through the Tafel reaction due to its large energy barrier. Furthermore, the P3-hollow sites also exhibit a low kinetic barrier for water dissociation, promoting HER in alkaline media. A series of electronic structure analyses were performed in gaining insights into the origin of the HER activity. First, the density of states (DOS) and crystal orbital Hamilton population (COHP) analyses revealed a favorable interaction of electronic states between P and H atoms, leading to stable H adsorption at P3-hollow sites. In addition, the Bader charge analysis demonstrates that the strength of H adsorption at P3-hollow sites linearly increases with the electrons carried by the latter. The optimal net charge on the P3-hollow sites leads to a desired ΔG H that is close-to-zero. Finally, a highly efficient electron transfer was observed between the P3-hollow sites and their neighboring atoms, facilitating the HER.

Au/TiO2 thin film with ultra-low content of gold: An efficient self-supported bifunctional electrocatalyst for oxygen and hydrogen evolution reaction

Electrochemical water splitting has triggered much attention for the cost-effective production of hydrogen (H2) to alleviate the energy crises around the globe. Searching for efficient and scale able electrode materials to efficiently catalyze both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) at low overpotential is direly needed. Herein we report a scalable method to develop a thin film of Au@TiO2 on fluorinated tin oxide (FTO) with ultra-low content of Au (0.573 µg/cm2), which can dramatically sensitize the mesoporous TiO2 for OER and HER in alkaline medium (1 M KOH). The thin film was developed via spin coating with layer-by-layer deposition of TiO2 and Au at optimum concentration and temperature. The catalyst needed a small overpotential of 200 and 240 mV for the HER and OER, revealing a sustainable behavior for more than 60 h, mainly depending on the nature of the thin film, uniformly distributed small particles of Au, and their oxidation states/orbital occupancy. It is anticipated that sensitization of thin film of mesoporous TiO2 with an ultrasmall amount of Au could simultaneously realize the role of synergistic interaction of Au and TiO2, the oxidation state of Au0/1+ and self-supported/free standing nature of electrodes which are indeed very appealing to facilitate the mass and charge transport during energy intense water splitting process. We believe that such a facile and scalable pathway could provide a guiding principle to rationally design more efficient electrode material with minimum use of precious metals for the viable electrochemical water splitting processes.

Enhanced water electrolysis activity by CoNi-LDH/Co -nitrogen-doped carbon heterostructure with dual catalytic active sites

The study and development of bifunctional non-precious metal catalysts with excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalytic activities are particularly important and challenging for electrocatalytic total water splitting. Here, we report a non-precious material constructed by growing cobalt-nickel double hydroxides on ZIF-derived Co nanoparticles and nitrogen-doped carbon framework (CoNi-LDH/Co@NC), which exhibits excellent electrocatalytic performances for both OER and HER in alkaline media. When used as OER and HER electrocatalysts, CoNi-LDH/Co@NC only needs 359 mV and 187 mV overpotentials at a current density of 100 mA cm−2, respectively. Surprisingly, using CoNi-LDH/Co@NC as both cathode and anode for a two-electrode water splitting system, a small battery voltage of 1.51 V is required at the current density of 10 mA cm−2, and the current density remained stable for 20 h without any obvious attenuation. This opens up new possibilities for further exploration of non-precious metal electrocatalysts for water splitting.

Redrawing HER Volcano with Interfacial Processes—The Role of Hydrogen Spillover in Boosting H2 Evolution in Alkaline Media

The requirements for the efficient replacement of fossil fuel, combined with the growing energy crisis, places focus on hydrogen production. Efficient and cost-effective electrocatalysts are needed for H2 production, and novel strategies for their discovery must be developed. Here, we utilized Kinetic Monte Carlo (KMC) simulations to demonstrate that hydrogen evolution reaction (HER) can be boosted via hydrogen spillover to the support when the catalyst surface is largely covered by adsorbed hydrogen under operating conditions. Based on the insights from KMC, we synthesized a series of reduced graphene-oxide-supported catalysts and compared their activities towards HER in alkaline media with that of corresponding pure metals. For Ag, Au, and Zn, the support effect is negative, but for Pt, Pd, Fe, Co, and Ni, the presence of the support enhances HER activity. The HER volcano, constructed using calculated hydrogen binding energies and measured HER activities, shows a positive shift of the strong binding branch. This work demonstrates the possibilities of metal–support interface engineering for producing effective HER catalysts and provides general guidelines for choosing novel catalyst–support combinations for electrocatalytic hydrogen production.

Understanding Cation Effects on the Hydrogen Evolution Reaction

The hydrogen evolution reaction (HER) is known to be influenced by the identity of alkali metal cations in the electrolyte. But a clear understanding of this behavior has not been developed. Here, we present the results of experimental and theoretical studies that describe how alkali metal cations influence the HER in acidic and basic electrolytes. Alkali metal cations are shown to have no systematic effect on HER rates in acid. In alkaline media, rates decrease with increasing cation size over Ir, Pd, and Pt (Li+ > Na+ > K+ > Cs+) and increase with cation size over Cu, Ag, and Au (Li+ < Na+ < K+ < Cs+). We argue that interfacial cations lower the activation barrier for water dissociation, an elementary step unique to the HER in alkaline media. HER rates are limited by this step on Cu, Ag, and Au but are not over Ir, Pd, and Pt, explaining the inverted activity trend. Based on ab initio molecular dynamics simulations, we suggest that trends with cation size are attributable to the greater willingness of large, weakly solvated cations to approach the electrode surface.

Ultrafast Preparation of Metal/Carbon Nanocomposite Electrocatalysts by Magnetic Induction Heating toward Efficient Hydrogen Evolution Reaction

Hydrogen, which can be readily produced by electrochemical water splitting, has been hailed as one of the most promising green energy sources. In a water electrolyzer, catalysts are needed for the hydrogen evolution reaction (HER) at the cathode, which are traditionally based on platinum-based materials. Recently, carbon-based nanocomposites have emerged as viable alternatives, which are mostly prepared by pyrolysis or wet chemistry methods, which are time- and energy-consuming. We have exploited magnetic induction heating (MIH) for ultrafast and green preparation of high-performance HER electrocatalysts. A novel MIH method was developed for the ultrafast and green preparation of carbon-supported Ru NPs toward HER in alkaline media, where the size and morphology of the Ru NPs can be readily manipulated by the heating current and duration. It is expected that MIH can be exploited for the design and engineering of high-performance nanocomposite catalysts for important electrochemical energy technologies.

Fabrication of Mo2C nanoparticles on N-doped carbon nanosheets as high-performance electrocatalyst

Molybdenum carbide is a promising material as electrocatalyst for hydrogen evolution reaction (HER). Herein, a facile strategy was proposed to prepare Mo-precursor by coordination of Mo with polysaccharide from natural biomass (jujube) at room temperature, which also acted as carbon and chelating agent. After the Mo-polysaccharide complex is carbonized, Mo2C nanoparticles (NPs) are highly dispersed on N-doped carbon matrix. In this process, nitrogen self-doping, lamellar carbon formation and molybdenum carbonization were achieved simultaneously, and particle aggregation is avoided. The results show that 2D carbon nanosheets-embedded Mo2C NPs is an excellent electrocatalyst for HER in alkaline medium. An overpotential of 124 mV at j = 10 mA cm−2 can be reached when the optimum Mo2C/NC-1.0 material as electrode material, and it is better than other Mo2C materials reported recently. The exceptional HER performance is originated from the 2D lamellar structure and rich-N atom from jujube source, which can accelerate electron transfer and change the electron density of Mo2C. This study opens a new avenue to design biomass-derived C/Mo2C used as catalyst in hydrogen-evolving reactions.

Inter-Electronic Interaction between Ni and Mo in Electrodeposited Ni-Mo-P on 3D Copper Foam Enables Hydrogen Evolution Reaction at Low Overpotential.

Electrocatalytic hydrogen evolution reaction (HER) via water electrolysis has been considered the most effective and sustainable route to produce clean hydrogen. Designing and structure optimization are the two important parameters to develop an affordable, easy to fabricate, and stable non-noble metal electrocatalyst for the production of hydrogen as a clean, sustainable, and green fuel. Herein, we have synthesized Ni-Mo-P on copper foam (Cuf) via a facile single-step electrodeposition method, which can show stratospheric efficiency toward HER with a Tafel slope of 67 mV dec-1 and a very low overpotential of only 53 mV at a current density of 20 mA cm-2. Cuf acts as a conducting substrate support and the existence of the inter-electronic effect between Ni and Mo results in substantial catalytic activity toward hydrogen generation. In addition to this, the catalyst shows long time stability of around 97.5 h with almost negligible degradation under the applied overpotential for HER in alkaline media. This work features the significance of structure design and construction of non-noble metal catalysts via a simple method for efficient hydrogen generation.

The effect of calcination temperature on the hydrogen evolution reaction performance of Co/NiCoP nano-heterojunction

The energy crisis makes it a challenge to develop cost-effective, efficient and stable electrocatalysts for hydrogen evolution reaction (HER). In this study, Co/NiCoP nano-heterojunctions grown on carbon cloth were reported for the first time through an electrochemical deposition - phosphatization strategy. Moreover, the effects of calcination temperature (300, 350, 400 and 450 °C) on the structure and morphology of the products were studied. The results reveal that: (a) Co/NiCoP with the morphology of nanoparticles (NPs) and nanoarrays (NAs) were fabricated under 300–350 °C and 450 °C, respectively; (b) increasing the calcination temperature lead to a decrease in the degree of crystallinity of Co/NiCoP catalysts, which was demonstrated by X-ray diffraction and X-ray photoelectron spectroscopy; (c) benefiting from structure and electronic state of electrocatalysts, the catalyst that is calcined at 350 °C ( Co/NiCoP-350 NPs) is optimal for HER in alkaline media, it required only 54 mV overpotential to achieve a current density of − 10 mA cm−2. Furthermore, the good stability of Co/NiCoP-350 NPs for HER in alkaline media.

Efficient hydrogen production of phosphonitrilic-bridged metal porphyrin porous covalent organic polymer with a push-pull motif

Rational design of efficient hydrogen evolution reaction (HER) electrocatalysts, constructed with earth-abundant elements, is critical for developing sustainable alternative energy sources. Herein, two phosphonitrilic-bridged metal porphyrin porous covalent organic polymers (COPs) were developed for HER. Compared to CoTPP-PCTCOP, NiTPP-PCTCOP exhibits relative low overpotentials of 140 to reach 10 mA cm−2 for HER in alkaline medium, which is comparable to many previously reported state-of-the-art electrocatalysts. The enhanced HER activity of NiTPP-PCTCOP is associated with its chemical composition and special push-pull structure. Long-term stability analysis of NiTPP-PCTCOP shows that the current density exhibits no obvious deactivation over a long time test. This work demonstrates an effective technique to develop promising HER electrocatalysts, highlighting its advantages by combing phosphonitrilic chloride trimer with metal porphyrins.