Efficient Electrocatalyst For Hydrogen Evolution Research Articles

Hierarchical Ni3S2@2D Co MOF nanosheets as efficient hetero-electrocatalyst for hydrogen evolution reaction in alkaline solution

Developing efficient and stable non-noble metal electrocatalysts for alkaline hydrogen evolution poses a challenge for current research. Herein, a novel hierarchical hetero-electrocatalyst of Ni3S2@2D Co MOF was synthesized with cobalt metal-organic frameworks (Co-MOFs) crystallization on carbon paper (CP) and in-situ electrodeposition of Ni3S2 nanosheets. The catalyst Ni3S2@2D Co-MOF/CP exhibited an excellent hydrogen evolution reaction (HER) activity with a low overpotential of 140 mV and a small Tafel slope of 90.3 mV dec−1 at a current density of -10 mA cm−2. This catalyst demonstrated a lower overpotential (395 mV) than commercial Pt/C catalyst at a high current density (>130 mA cm−2). The efficient and stable HER performance of Ni3S2@2D Co-MOF/CP was attributed to nickel sulfide honeycomb nanosheets grown on two-dimensional MOF frameworks, which were conducive to charge transfer and hydrogen evolution. The electron-rich nickel sulfide surface significantly diminished H* adsorption and reduced energy barrier of H2 generation to promote HER process. This work provides a new strategy for practical preparation of efficient and stable transition metal electrocatalysts.

2D/2D/1D Structure of a Self-Supporting Electrocatalyst for Efficient Hydrogen Evolution

2D/2D/1D Structure of a Self-Supporting Electrocatalyst for Efficient Hydrogen Evolution

Anchoring ultrafine molybdenum phosphide on hierarchical three-dimensional CNTs/rGO framework as efficient electrocatalysts for hydrogen evolution

Anchoring ultrafine molybdenum phosphide on hierarchical three-dimensional CNTs/rGO framework as efficient electrocatalysts for hydrogen evolution

Achieving highly efficient pH-universal hydrogen evolution by superhydrophilic amorphous/crystalline Rh(OH)3/NiTe coaxial nanorod array electrode

Design of high-performance pH-universal electrocatalysts is critical to practical large-scale hydrogen generation as a carbon-neutral fuel, yet challenging. Herein, we report an unique motif with crystalline nickel tellurium nanorods enclosed by amorphous rhodium hydroxide (a-Rh(OH)3/NiTe), formed through a hydrothermal synthesis and a subsequent chemical etching process, to address this challenge. The as-prepared a-Rh(OH)3/NiTe cathode enables a current density of 100 mA cm−2 with low overpotentials of 51, 109, and 64 mV for HER in alkaline, neutral and acidic media, respectively. As revealed by density functional theory (DFT) calculations, the electronic interactions between a-Rh(OH)3 and NiTe enhance the performance of Rh active sites. More importantly, the motif possesses superhydrophilicity and aerophobicity features, which not only facilitates the access to electrolytes but also ensures the fast release of hydrogen bubbles, endowing the electrocatalyst with advanced pH-universal HER activity. This work provides insights for the design of highly efficient electrocatalysts for hydrogen evolution at both molecular and mesoscopic levels.

Ultra-small-sized multi-element metal oxide nanofibers: an efficient electrocatalyst for hydrogen evolution.

Compared to noble metals, transition metal oxides (TMOs) have positive development prospects in the field of electrocatalysis, and the synergy between the elements in multi-element TMO-based materials can improve their catalytic activity. However, it is still a challenge to synthesize multi-component TMO-based catalysts and deeply understand the effects of components on the catalytic performance of the catalysts. Here, we demonstrate multi-element ultra-small-sized nanofibers for efficient hydrogen production. The ternary NiFeCoO nanofiber-based electrode reached an overpotential of 82 mV at the current density of 10 mA cm−2 with a Tafel slope of 56 mV dec−1 in 1 M KOH, which are close to those of Pt plate (66 mV at 10 mA cm−2; the Tafel slope is 32 mV dec−1). In addition, the current density maintained 97% of its initial value after 10 h operation. We used the ternary NiFeCoO nanofiber-based electrode as an efficient counter electrode in photoelectrochemical hydrogen production to demonstrate the versatility of these nanofibers.

Self-assembled ultrasmall mixed Co–W phosphide nanoparticles on pristine graphene with remarkable synergistic effects as highly efficient electrocatalysts for hydrogen evolution

Pristine graphene supported ultrasmall, highly dispersed, and high-density Co–W–P nanoparticles were synthesized via phosphotungstic-acid-mediated self-assembly, showing superior HER catalytic performance.

MoS2 quantum dot-decorated MXene nanosheets as efficient hydrogen evolution electrocatalysts

A controllable assembly strategy is developed to fabricate 0D MoS2 quantum dots anchored onto 2D Ti3C2Tx MXene nanosheets, which show exceptional electrocatalytic ability toward the hydrogen evolution reaction.

A doping-adsorption-pyrolysis strategy for constructing atomically dispersed cobalt sites anchored on a N-doped carbon framework as an efficient bifunctional electrocatalyst for hydrogen evolution and oxygen reduction.

Renewable energy technology development focuses on the exploration of economical and efficient non-precious metal catalysts to replace precious metal catalysts in electrocatalytic reactions including oxygen reduction (ORR) and hydrogen evolution (HER). Herein, we synthesized a cobalt single atom catalyst anchored on a N-doped carbon framework by a doping-adsorption-pyrolysis strategy. The optimized Co SAs/CN-3 catalyst showed excellent HER and ORR bifunctional electrocatalytic performance, which could be attributed to the highly dispersed Co–N4 active sites, large specific surface area and abundant pore structure. Density functional theory shows that the isolated active Co–N4 site shows low hydrogen adsorption Gibbs free energy, and promotes the adsorption of H and oxygen-containing intermediates in HER and ORR. This work not only provides a new idea for the construction of transition metal catalysts with atomic accuracy but also provides powerful guidance for the development of efficient bifunctional electrocatalysts.

Porous FeP supported on 3D nitrogen-doped carbon fibers as efficient electrocatalysts for wide-pH hydrogen evolution

A novel porous iron phosphide loading on nitrogen-doped carbon fiber/carbon paper (p-FeP/NCF/CP) as highly effective self-supporting catalysts for the hydrogen evolution reaction is synthesized by a three-step approach.

Nanostructured Pt-doped 2D MoSe2: an efficient bifunctional electrocatalyst for both hydrogen evolution and oxygen reduction reactions.

Two-dimensional transition metal dichalcogenides (TMDs) are a new family of 2D materials with features that make them appealing for potential applications in nanomaterials science and engineering. Recently, these 2D TMDs have attracted significant research interest because of the abundant choice of materials with diverse and tunable electronic, optical, chemical, and electrocatalytic properties. Although, the edges of the 2D TMDs show excellent electrocatalytic performance, their basal plane (001) is inert, which hinders their industrial applications for electrocatalysis. Transition metal/chalcogen atom vacancies or doping with some other foreign atoms may be a remedy to activate the inert basal plane. Here, we have computationally designed 2D monolayer MoSe2 and studied its electronic properties with electrocatalytic activities. A Pt-atom has been doped in the pristine 2D MoSe2 (i.e., Pt-MoSe2) to activate the inert basal plane resulting in a zero band gap. This study reveals that the Pt-MoSe2 is an excellent bifunctional electrocatalyst for both the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) with the aid of first priciples-based hybrid density functional theory (DFT). The periodic hybrid DFT method has been applied to compute the electronic properties of both the pristine MoSe2 and Pt-MoSe2. To determine both the HER and ORR mechanisms on the surface of the Pt-MoSe2 material, non-periodic DFT calculation has been performed by considering a molecular Pt1-Mo9Se21 cluster model. The present study shows that the 2D Pt-MoSe2 follows the Volmer-Heyrovsky mechanism for the HER with energy barriers of about 9.29 kcal mol-1 and 10.55 kcal mol-1 during the H˙-migration and Heyrovsky reactions. The ORR is achieved by a four-electron transfer mechanism with the formation of two transition energy barriers of about 14.94 kcal mol-1 and 11.10 kcal mol-1, respectively. The lower energy barriers and high turnover frequency during the reactions expose that the Pt-MoSe2 can be adopted as an efficient bifunctional electrocatalyst for both the HER and ORR. The present studies demonstrate that the exceptional HER and ORR activity and stability performance shown by the MoSe2 electrocatalyst can be enhanced by Pt-doping, opening a promising concept for the sensible design of high-performance catalysts for H2 production and O2 reduction.

Facile and rapid synthesis of Pt-NiOx/NiF composites as a highly efficient electrocatalyst for alkaline hydrogen evolution

A highly efficient and stable catalyst is the goal of practical electrolysis of water for hydrogen production. Here, Pt-NiOx nanocomposites anchoring on Ni foam (Pt-NiOx/NiF) is synthesized by a flexibility galvanic replacement within 2 h and manifests a considerable application prospect for hydrogen evolution reaction (HER) in alkaline media. Owing to the faster kinetics result from appropriate noncovalent interaction, Pt-NiOx/NiF achieved respectively a factor of 12 and 1.8 enhancement in HER current density relative to NiOx/NiF and commercial Pt/C at an overpotential of 200 mV. Moreover, such a heterogeneous electrocatalyst have demonstrated a superior long-term stability of 100 h at a high current density of 50 mA/cm2. The low cost, easy scalable synthetic strategy and exceptional HER activity makes the industrial application of Pt-NiOx/NiF possible.

Quasi-parallel nickel cobalt phosphide nanosheet arrays as highly efficient electrocatalyst for hydrogen evolution and overall water splitting at large current densities

Developing electrocatalysts with high activity for the hydrogen evolution reaction (HER) is a key prerequisite for overall water splitting. Herein, quasi-parallel NiCo phosphide (NiCoP) nanosheet arrays exhibiting a domain arrangement are grown onto Ni foam via a facile hydrothermal process followed by phosphorization. Benefiting from the strong interaction between Ni foam substrate and the as-loaded materials, quasi-parallel NiCo phosphide nanoarrays exhibit low resistance nature, high electrocatalytic activity and excellent stability toward HER in pH-universal electrolytes. Especially, it delivers the overpotential of 53 mV, 55 mV and 92 mV at 10 mA cm −2 in acidic, alkaline and neutral media, respectively. Impressively, the catalyst shows large current densities of 1000 mA cm −2 at low overpotentials, outperforming that of the commercial precious metal-based catalysts as well as the NiCoP nanosheet arrays with random alignment. Moreover, this novel and highly active catalyst enables a water splitting electrolyzer operating at the cell voltage of 1.49 V and 1.85 V to offer 10 mA cm −2 and 500 mA cm −2 in 1.0 M KOH at room temperature, together with high durability. • Quasi-parallel NiCoP nanosheet arrays with domain pattern are grown on Ni foam. • Enhanced interaction between NiCoP nanosheet arrays and Ni substrate. • HER Overpotentials of 53 and 55 at 10 mA/cm 2 in acidic and alkaline media. • Deliver 500 and 1000 mA/cm 2 at 171 mV and 193 mV in KOH solution for HER. • 1.49 V and 1.85 V to drive 10 and 500 mA/cm 2 for overall water splitting.

Inside Back Cover: Hydrogen production coupled with water and organic oxidation based on layered double hydroxides (EXP2 3/2021)

In the cover of article number 20210050, Mingfei Shao and colleagues present an overview of latest progress of hydrogen production from perspectives of designing efficient LDHs-based electrocatalysts for OER and electrochemical hydrogen-evolution coupled with alternative oxidation (EHCO). The challenges and prospective in this promising research field were concluded, hoping to provide inspiration for the development of low-cost hydrogen production technology.

Atomically Dispersed, Low-Coordinate Co-N Sites on Carbon Nanotubes as Inexpensive and Efficient Electrocatalysts for Hydrogen Evolution.

Hydrogen produced using renewable electricity is considered the key to achieving a low-carbon energy economy. However, the large-scale application of electrochemical water splitting for hydrogen evolution currently requires expensive platinum-based catalysts. Therefore, it is important to develop efficient and stable catalysts based on the rich reserves of transition metals as alternatives. In this study, the authors prepare a carbon-nanotube material enriched with atomically dispersed CoN sites having uniquely low coordination numbers via the simple mixing, pyrolysis, and leaching of inexpensive precursors. These atomically dispersed low-coordinate CoN sites provide an overpotential of only 82mV at 10mA cm-2 for the hydrogen evolution reaction (HER) under challenging acidic conditions and show excellent durability in accelerated stability tests. Theoretical simulations also confirm that these unique, low-coordinate CoN2 sites have lower energy barriers in catalyzing the HER than Fe/NiN2 sites and commonly reported CoN3 /N4 sites. Therefore, the method provides a new concept for the design of single-atom catalytic sites with low coordination numbers. It also serves to reduce the cost of hydrogen production in the future owing to the high catalytic activity, low cost, and scalable production process.

Phase-mediated cobalt phosphide with unique core-shell architecture serving as efficient and bifunctional electrocatalyst for hydrogen evolution and oxygen reduction reaction

Hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) have been considered as two critical processes in the field of electrocatalytic water-splitting for hydrogen production and fuel cells. However, the sluggish reaction kinetics of HER and ORR required efficient electrocatalyst such as Pt to promote such process. Transition metal phosphides (TMPs) exhibit great potential to replace noble metal electrocatalysts to accelerate HER and ORR due to their high activity and easy availability. Herein, a highly-efficient bifunctional CoP electrocatalyst for HER and ORR, featuring a unique core-shell structure decorated on nitrogen-doped carbon matrix was designed and constructed via etching a cobalt-based zeolitic imidazolate framework (ZIF-67) with phytic acid (PA) followed by pyrolysis treatment (PA-ZIF-67–900). Experimental results revealed that the pure-phase single-crystalline CoP exhibited outstanding electrocatalytic performance in HER and ORR, superior to Co(PO3)2 in PA-ZIF-67–700, hybrid phase of Co(PO3)2 and CoP in PA-ZIF-67–800 and Co2P-doped CoP in PA-ZIF-67–1000. To reach the current density of 10 mA/cm2 the as-synthesized CoP required an overpotential of 120 mV for HER in 1 mol/L KOH and half-wave potential of 0.85 V in O2-saturated 0.1 mol/L KOH. This work present new clue for construction of efficient and bifunctional electrocatalyst in the field of energy conversion and storage

Microwave-Assisted Auto-Combustion Synthesis of Binary/Ternary Co x Ni1-x Ferrite for Electrochemical Hydrogen and Oxygen Evolution.

Enormous efforts have been dedicated to engineering low-cost and efficient electrocatalysts for both hydrogen evolution and oxygen evolution reactions (HER and OER, respectively). For this, the current contribution reports the successful synthesis of binary/ternary metal ferrites (CoxNi1–xFerrite; x = 0.0, 0.1, 0.3, 0.5, 0.7, and 1.0) by a simple one-step microwave technique and subsequently discusses its chemical and electrochemical properties. The X-ray diffraction analysis substantiated the phase purity of the as-obtained catalysts with various compositions. Additionally, the morphology of the nanoparticles was identified via transmission electron microscopy. Further, the vibrating sample magnetometer justified the ferromagnetic character of the as-prepared products. The electrochemical measurements revealed that the as-prepared materials required the overpotentials of 422–600 and 419–467 mV for HER and OER, respectively, to afford current densities of 10 mA cm–2. In the general sense, Ni cation substitution with Co influenced favorably toward both HER and OER. Among all synthesized electrocatalysts, Co0.9Ni0.1Ferrite displayed the highest performance in terms of OER in 1 M KOH solution, which is related to the synergistic effect of multiple parameters including the optimal substitution amount of Co, the highest Brunauer–Emmett–Teller surface area, the smallest particle size among all samples (26.71 nm), and the lowest charge transfer resistance. The successful synthesis of ternary ferrites carried out for the first time via a microwave-assisted auto-combustion route opens up a new path for their applications in renewable energy technologies.

Rational construction of uniform CoS/NiFe2O4 heterostructure as efficient bifunctional electrocatalysts for hydrogen evolution and oxygen evolution reactions

The development of efficient bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline environment is crucial and challenging for large-scale hydrogen energy application. Herein, a heterostructure electrocatalyst on Ni foam (NF) with CoS nanosheet coupled with NiFe2O4 was synthesized via electrodeposition method with the assistant of thiourea followed by annealing treatment. Because of the unique three-dimension structure, this self-supported catalyst possesses high intrinsic conductivity, abundant active sites and excellent durability, acting as an exceptionally durable and efficient catalyst for HER and OER. The obtained CoS/NiFe2O4-15/NF exhibits HER and OER catalytic performance with overpotentials of 116 mV and 227 mV at a current density of 10 mA cm−2 in 1 M KOH, respectively. For CoS/NiFe2O4-15/NF||CoS/NiFe2O4-15/NF two-electrode system, the electrolyser requires 1.60 V to deliver 10 mA cm−2, and negligible loss of activity is observed after working for 12 h (10 mA cm−2). Moreover, the interface between oxide and sulfide is identified to play a major part in the catalysis of OER and HER. These excellent properties of CoS/NiFe2O4-15/NF electrode advance the electronic water splitting reaction for hydrogen production.

Facile synthesis of tubular CoP as a high efficient electrocatalyst for pH-universal hydrogen evolution

A facile three-step approach for tubular CoP preparation and its catalytic activity for HER and OER are reported. The CoP microtubes show superior HER performance in a wide pH range with low overpotentials of 91, 101 and 113 mV at 10 mA cm−2 in 0.5 M H2SO4, 1 M KOH and 1 M PBS, respectively. Additionally, it also depicts superior OER performance with an overpotential of 300 mV at 10 mA cm−2, which is lower than reported precious metal oxides. The improved electrocatalytic performance of tubular CoP is likely attributed to the porous tube-like structural features, which not only afford rich exposed active sites, but also accelerate the charge or mass transfer efficiency, and thus efficiently promote the HER performance. The synthesis of tubular CoP confirms the importance of morphology features and provides a new insight to rationally design and synthesize highly effective non-noble metal phosphide-based pH-universal electrocatalysts for HER.

Construction of an N-Decorated Carbon-Encapsulated W2C/WP Heterostructure as an Efficient Electrocatalyst for Hydrogen Evolution in Both Alkaline and Acidic Media.

Tungsten carbide (W2C) has emerged as a potential alternative to noble-metal catalysts toward hydrogen evolution reaction (HER) owing to its Pt-like electronic configuration. However, unsatisfactory activity, dilatory electron transfer, and inefficient synthesizing methods, especially for nanoscale particles, have severely hindered its large-scale applications. Herein, a novel heterostructure composed of W2C and tungsten phosphide (WP) embedded in nitrogen-decorated carbon (W2C/WP@NC) was constructed as an efficient HER electrocatalyst. The as-prepared W2C/WP@NC catalyst exhibits remarkable electrocatalytic activity and robust durability toward HER both in acids and bases. More notably, the W2C/WP@NC catalyst demonstrates low overpotentials of 116.37 and 196.2 mV to afford a current density of 10 mA cm-2 and reveals slight potential decays of about 6.4 and 7.64% over 12 h continuous operation in bases and acids, respectively. The overall water-splitting performance was further evaluated using the W2C/WP@NC catalyst as the cathode and commercial RuO2 as the anode in an electrolyzer, which can realize an overall current density of 10 mA cm-2 and maintain long durability of more than 12 h with a small cell voltage of 1.723 V. This work opens up new opportunities for exploring cost-efficient electrocatalysts in sustainable energy conversion.

A nickel(II) complex of 2,6-pyridinedicarboxylic acid ion, an efficient electro-catalyst for both hydrogen evolution and oxidation

A new electrocatalyst based on a nickel complex, [Ni(HL)2], is designed and provided by the reaction of NiCl2 with 2,6-pyridinedicarboxylic acid (H2L) in our group. Electrochemical investigations show that [Ni(HL)2] can electro-catalyze hydrogen evolution from acetic acid with a rate constant of 3454 M−2 s−1. [Ni(HL)2] also can electro-catalyze hydrogen oxidation with a rate constant of 2.047 × 104 M−2 s−1. The carboxyl group of [Ni(HL)2] may play critical roles in the catalytic hydrogen evolution and oxidation reactions. Moreover, the introduction of an electron-withdrawing group, -Cl at the pyridine of H2L leads to a decrease in the catalytic activity for hydrogen generation, and [Ni(HL)2] shows a more efficient activity than [Ni(HL-Cl)2] (H2L-Cl: 4-chloro-2,6-pyridinedicarboxylic acid). These findings can afford a new ideal for the design of electrocatalysts for both H2 evolution and H2 oxidation.