pH-universal Electrocatalysts For Hydrogen Evolution Reaction Research Articles

Ru Regulated Electronic Structure of PdxCuy Nanosheets for Efficient Hydrogen Evolution Reaction in Wide pH Range.

The development of highly effective catalysts for hydrogen evolution reaction (HER) in a wide pH range is crucial for the sustainable utilization of green energy utilization, while the slow kinetic reaction rate severely hinders the progress of HER. Herein, the reaction kinetic issue is solved by adjusting the electronic structure of the Ru/PdxCuy catalysts. The champion catalyst displays a remarkable performance for HER with the ultralow overpotential (27, 28, and 97mV) in 1.0m KOH, 0.5m H2SO4, and 1.0m PBS at 10mA cm-2 and high the mass activity (3036 A g-1), respectively, superior to those of commercial Pt/C benchmarks and most of reported electrocatalysts, mainly due to its low reaction activation energy. Density functional theory (DFT) calculations indicate that Ru doping contributes an electron-deficient 3d band, which promotes water adsorption. Additionally, this also leads to an upward shift of the d-band center of Pd and a downward shift of the d-band center of Cu, further optimizing the adsorption/dissociation of H2O and H*. Results from this work may provide an insight into the design and synthesis of high-performance pH-universal HER electrocatalysts.

Interface regulation of Zr-MOF/Ni2P@nickel foam as high-efficient electrocatalyst for pH-universal hydrogen evolution reaction

Currently, the development of economical and effective non-noble metal electrocatalysts is vital for advancing hydrogen evolution reaction (HER) and enabling its widespread applications. The customizable pore structure and enormous surface area of metal–organic frameworks (MOFs) have made them to become promising non-noble metal electrocatalysts for HER. However, MOFs have some challenges, including low conductivity and instability, which can result in them having high overpotentials and slow reaction kinetics in electrocatalytic processes. In this work, we present an innovative approach for synthesizing cost-effective and high-efficient Zr-MOF-derived pH-universal electrocatalysts for HER. It entails creating the interfaces of the electrocatalysts with suitable proportions of phosphide nanostructures. Zr-MOF/Ni2P@nickel foam (NF) electrodes with interface regulated by Ni2P nanostructures were successfully developed for high-efficient pH-universal HER electrocatalysts. The presence of Ni2P nanostructures with abundant active sites at the Zr-MOFs@NF interfaces boosted the electronic conductivity and local charge density of the hybrid electrocatalysts. This helped to improve their reaction kinetics and electrocatalytic activity. By optimizing the Ni2P amount, Zr-MOF/Ni2P@NF demonstrated impressive stability and superior HER activities, with a low overpotential of 149 mV (acidic electrolytes) and 143 mV (alkaline electrolytes) at 10 mA cm−2. The proven strategy in this work can be expanded to many types of MOF-based materials for wider practical applications.

Phase transition engineering of nanoporous pyrite-phase NiSe2 foam by phosphorus doping for robust pH-universal hydrogen evolution

The present non-precious hydrogen-evolving electrocatalysts deliver high catalytic activity either in acidic or basic media but very few simultaneously exhibit superb catalytic efficiency and stability for hydrogen evolution reaction (HER) in a wide pH range, especially for pyrite-phase materials (e.g., CoS2, NiSe2), probably due to their high kinetic energy barriers of initial water dissociation process. Herein, we report a phase transition engineering of pyrite-phase porous NiSe2 into NiP1.86Se0.14 by heavy phosphorus doping, which performs excellently as a pH-universal electrocatalyst for HER. In this material, P atom replaces the sub-selenium atom in NiSe2 to modulate the electronic structures and spin states of Ni sites with lower d-band center, thus promoting sluggish hydrogen adsorption, water adsorption, and dissociation dynamics. As a result, this catalyst exhibits superior hydrogen-evolving catalytic activity in multiple media in terms of relatively low overpotentials of 56.8 and 79 mV at a current density of 10 mA cm−2 in 0.5 M H2SO4 and 1.0 M KOH, respectively. Particularly, this porous NiP1.86Se0.14 shows good stability toward hydrogen evolution in both acidic and alkaline media, with little variation in potentials after continuous operation for approximately 80 and 70 h at 30 mA cm−2. This work may provide a promising solution to address the poor catalytic HER activity and instability of transition metal selenides under alkaline conditions.

Enhancing the electronic metal-support interaction of CoRu alloy and pyridinic N for electrocatalytic pH-universal hydrogen evolution reaction

The construction of efficient pH-universal hydrogen evolution reaction (HER) electrocatalysts remain enormous challenges for hydrogen production from water electrolysis. Herein, we reported a HER electrocatalyst composed of cobalt-ruthenium alloy nanoparticles with the synergy of pyridinic N (CoRu/NC-700). CoRu/NC-700 exhibits excellent HER performance and stability in acidic, alkaline and neutral media, and can reach 10 mA cm−2 with overpotential of only 6, 10 and 30 mV, respectively. Especially in alkaline and acidic media, overpotential of only 217 and 227 mV are required to achieve 1000 mA cm−2, respectively, which is of great significance for industrialized hydrogen produced by electrolysis of water. KSCN and H3PO4 poisoning experiments prove that such high HER activity is attributed to the synergistic enhancement effect of pyridinic N on CoRu nanoparticles. This work will lay the foundation for the designing and development of novel and efficient pH-universal HER electrocatalysts.

Identification of single-atom-anchored g-CN as pH universal photo- and electro- catalysts for hydrogen evolution

Identifying efficient and low-cost catalysts for electrocatalytic and photocatalytic hydrogen evolution reaction (HER) is critical for renewable energies, yet it remains an immense challenge. Through density functional theory calculations, we systematically investigate the great potential of 30 single-atom catalysts (SACs), namely single-atom-anchored g-CN (M/g-CN), toward electrocatalytic and photocatalytic HER in all pH intervals. Through Gibbs free energy (ΔGH*) calculations, electrical conductivity as well as water dissociation kinetic analysis, six M/g-CN (M = Sc, Ti, V, Ga, Sn, Au) are identified as pH universal electrocatalysts for HER. After excluding the influence of charge and solvation on ΔGH*, M/g-CN (M = V, Ga, Sn, Au) can still be regarded as potential pH universal electrocatalysts for HER. In addition, by combination of band structures with ΔGH* assessments, five M/g-CN (M = Ti, Ni, Ru, Pd, Os) are expected to be pH universal photocatalysts for HER. In particular, Ti/g-CN and Pd/g-CN possess favorable solar light harvesting and proton reducing kinetics, which can be regarded as the essential photo-electro integrated catalysts for HER. Moreover, employing machine learning method, the activity origin for HER on SACs is unveiled, and it is demonstrated that the charge transfer plays the decisive impact accompanied by the synergy effect from a series of structural characteristics. This work gives a new approach to design and search potential HER catalysts.

Atomically dispersed Ni–Ru–P interface sites for high-efficiency pH-universal electrocatalysis of hydrogen evolution

Designing catalysts with specific active sites is a crucial yet challenging task for high-efficiency electrocatalysis of hydrogen evolution reaction (HER). In this paper, we report the construction of atomically dispersed Ni–Ru–P interface sites (ISs) on Ru single-atomic sites doped nickel phosphide nanoparticles (Ru SAs–Ni 2 P NPs) with high-efficiency HER performances in a wide pH range. Especially, the as-constructed atomically dispersed Ni–Ru–P ISs on 2.20 wt% Ru SAs–Ni 2 P showed a highly active for catalyzing HER with high turnover frequencies at low overpotential, featuring a high mass activity as well as a superior stability under alkaline conditions. Based on the operando X-ray absorption spectroscopy experiments indicated that the Ni–Ru–P ISs plays an active role in the process of HER and participates in the catalytic process. Density functional theory calculations exhibited that the strong interaction in the atomically dispersed Ni–Ru–P ISs results in an optimized the hydrogen adsorption energy and an elevated hydroxyl adsorption energy, both of which help improve the HER performances. Notably, this work provides a new perspective for the design of high-efficiency HER electrocatalysts by constructing atomically dispersed ISs. In this paper, the atomically dispersed Ni–Ru–P interface sites (ISs) on Ru single-atomic sites doped nickel phosphide (Ru SAs–Ni 2 P) are successfully constructed, which display high-efficiency HER performances in a wide pH range. Especially, the as-constructed atomically dispersed Ni–Ru–P ISs on 2.20 wt% Ru SAs–Ni 2 P show highly active for catalyzing HER under alkaline conditions. The operando X-ray absorption spectroscopy experiments and density functional theory calculations indicate that the Ni–Ru–P ISs plays an active role in the process of HER and participates in the catalytic process. Thereby, this work provides a new perspective for the design of high-efficiency HER electrocatalysts by constructing atomically dispersed ISs. • Ru single-atomic sites doped nickel phosphide (Ru SAs–Ni 2 P) catalysts are prepared. • Atomically dispersed Ni–Ru–P interfacial sites (ISs) are constructed in Ru SAs–Ni 2 P. • Ni–Ru–P ISs can be used as high-efficiency pH-universal electrocatalysts for HER. • Operando XAS experiments reveal that the Ni–Ru–P ISs plays an active role for HER. • DFT indicate that Ni–Ru–P ISs are favorable for adsorption of H + and H 2 O molecules.

Platinum-rhodium alloyed dendritic nanoassemblies: An all-pH efficient and stable electrocatalyst for hydrogen evolution reaction

Hydrogen evolution reaction (HER) is regarded as a feasible strategy for producing high-purity hydrogen from abundant water. It is significant yet challenging for synthesis of Pt-based pH-universal HER electrocatalysts by substantially reducing the Pt loading without any decay in the activity. Herein, bimetallic PtRh alloyed dendritic nanoassemblies (DNAs) were efficiently prepared by a facile one-pot solvothermal strategy in oleylamine (OAm), coupling with the aid of glycine and cetyltrimethylammonium chloride (CTAC). By virtue of the unique branch-like structures and compositions advantages, the PtRh DNAs catalyst showed steeply enhanced HER activity with small overpotentials (i.e. 28 mV in 1.0 M KOH, 23 mV in 1.0 M phosphate buffer solution and 27 mV in 0.5 M H2SO4) at the current density of 10 mA cm−2, surpassing those of commercial Pt/C under such conditions. This work provides a facile and rational strategy to construct advanced Pt-based bimetallic electrocatalyst for energy-correlated applications.

CoMo-bimetallic N-doped porous carbon materials embedded with highly dispersed Pt nanoparticles as pH-universal hydrogen evolution reaction electrocatalysts.

The hydrogen evolution reaction is a key half reaction for water electrolysis and is of great significance. Pt-based nanomaterials are promising candidates for HER electrocatalysts. However, the high price of platinum and poor durability impede their practical applications. Herein, a new CoMo-bimetallic hybrid zeolite imidazolate framework is employed to load Pt nanoparticles in a highly dispersed manner as a precursor to synthesize an efficient pH-universal HER electrocatalyst (PtCoMo@NC), which displays overpotentials of 26, 51, and 66 mV at a current density of 10 mA cm-2 in acidic, basic, and neutral media, respectively. The strong synergistic effect of highly dispersed multi-type catalytic species, including cobalt, molybdenum carbide, and platinum (4.7%) promotes the catalytic activity in the HER process. Meanwhile, the aggregation of Pt nanoparticles is greatly restrained by the carbon matrix so that a brilliant long-time durability of 12 hours and a negligible current decrease in the LSV curve after 10 000 CV cycles are achieved.

Hierarchical Bimetallic Ni-Co-P Microflowers with Ultrathin Nanosheet Arrays for Efficient Hydrogen Evolution Reaction over All pH Values.

Designing efficient nonprecious catalysts with pH-universal hydrogen evolution reaction (HER) performance is of importance for boosting water splitting. Herein, a self-template strategy based on Ni-Co-glycerates is developed to prepare bimetallic Ni-Co-P microflowers with ultrathin nanosheet arrays. The highly porous core-shell structure gives rise to affluent mass transfer channels and availably prevents the aggregation of nanosheets, while the ultrathin nanosheets are favorable for producing abundant active sites. Besides, the produced CoP/NiCoP heterostructure in the bimetallic Ni-Co-P catalyst has excellent HER performance in a wide pH range. The as-prepared catalyst shows low potentials of 90, 157, and 121 mV to deliver a current density of 10 mA cm-2 in 0.5 M H2SO4, 0.5 M PBS, and 1 M KOH solution, respectively. Meanwhile, negligible overpotential decay is achieved in the polarization curves after a long-term stability determination. This work supplies a promising strategy for developing pH-universal HER electrocatalysts based on solid-state metal alkoxides.

Hierarchically Porous W-Doped CoP Nanoflake Arrays as Highly Efficient and Stable Electrocatalyst for pH-Universal Hydrogen Evolution.

It is still challenging to develop high-efficiency and low-cost non-noble metal-based electrocatalysts for hydrogen evolution reaction (HER) in pH-universal electrolytes. Herein, hierarchically porous W-doped CoP nanoflake arrays on carbon cloth (W-CoP NAs/CC) are synthesized via facile liquid-phase reactions and a subsequent phosphorization process. The W-CoP NAs/CC hybrid can be directly employed as a binder-free electrocatalyst and delivers superior HER performance in pH-universal electrolytes. Especially, it delivers very low overpotentials of 89, 94, and 102 mV to reach a current density of 10 mA cm-2 in acidic, alkaline, and neutral electrolytes, respectively. Furthermore, it shows a nearly 100% Faradaic efficiency as well as superior long-term stability with no decreasing up to 36 h in pH-universal electrolytes. The outstanding electrocatalytic performance of W-CoP NAs/CC can be mainly attributed to the porous W-doped nanoflake arrays, which not only afford rich exposed active sites, but also accelerate the access of electrolytes and the diffusion of H2 bubbles, thus efficiently promoting the HER performance. This work provides a new horizon to rationally design and synthesize highly effective and stable non-noble metal phosphide-based pH-universal electrocatalysts for HER.

Vanadium and nitrogen co-doped CoP nanoleaf array as pH-universal electrocatalyst for efficient hydrogen evolution

Exploring electrocatalysts which efficiently perform the hydrogen evolution reaction (HER) catalytic activity over wide pH range is greatly important for water splitting, however, remains enormous challenge. Herein, the host catalyst of CoP nanoarray on carbon cloth is co-doped with the guest elements of vanadium and nitrogen to acquire tuned electronic characteristics and additional active sites for improved HER activity. The electrochemical measurements show that the as-obtained V, N-CoP is endowed with smaller overpotentials and Tafel slopes than V-CoP and CoP. Impressively, V, N-CoP only needs low overpotentials of 57, 146, and 81 mV at 10 mA cm−2 in 1 M KOH, 1 M phosphate buffer, and 0.5 M H2SO4, respectively. This study sets a blueprint for developing pH-universal HER electrocatalysts via metal and nonmetal elements co-doping engineering.

Hierarchical Porous Co9S8/Nitrogen-Doped Carbon@MoS2 Polyhedrons as pH Universal Electrocatalysts for Highly Efficient Hydrogen Evolution Reaction.

The development of highly active and stable earth-abundant electrocatalysts to reduce or eliminate the reliance on noble-metal based ones for hydrogen evolution reaction (HER) over a broad pH range remains a great challenge. Herein, hierarchical porous Co9S8/N-doped carbon@MoS2 (Co9S8/NC@MoS2) polyhedrons have been synthesized by a facile hydrothermal approach using highly conductive Co/NC polyhedrons composed of cobalt nanoparticles embedded in N-doped carbon matrices as both the structural support and cobalt source. The Co/NC polyhedrons were prepared by direct carbonization of Co-based zeolitic imidazolate framework (ZIF-67) in Ar atmosphere. Benefiting from the prominent synergistic effect of N-doped carbon enhancing the conductivity of the hybrid, MoS2 and Co9S8 providing abundant catalytically active sites as well as the well-defined polyhedral structure promoting mechanical stability, the as-synthesized Co9S8/NC@MoS2 shows excellent HER activity and good stability over a broad pH range, with onset overpotentials of 4, 38, and 45 mV, Tafel slopes of 60.3, 68.8, and 126.1 mV dec-1, and overpotentials of 67, 117, and 261 mV at 10 mA cm-2 in 1.0 M KOH, 0.5 M H2SO4, and 1.0 M phosphate buffer solution (PBS), respectively. This work provides a general and promising approach for the design and synthesis of inexpensive and efficient pH-universal HER electrocatalysts.