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Designing efficient and robust oxygen evolution reaction (OER) electrocatalysts is of great importance for various electrochemical energy storage and conversion applications. Herein, we developed IrP2 nanocrystals uniformly anchored in P,N-codoped carbon nanosheets (IrP2@PNC-NS) as highly active OER electrocatalysts. The ultrathin PNC-NS reconstructs an agaric-like porous structure, which can inhibit the agglomeration of the IrP2 nanocrystals effectively. Moreover, the in-situ phosphatization leads to the formation of a strong electron interaction between PNC-NS and IrP2 nanocrystals, endowing the heterostructure materials with satisfying synergistic effects. Benefiting from the collaborative advantages of ideal configuration structure and favorable synergistic effects, IrP2@PNC-NS exhibits excellent OER performance with a low overpotential of 221 mV at 10 mA cm−2, and a small Tafel slope of 37.5 mV dec−1. DFT calculations reveal that the synergistic effects derived from the IrP2/PNC interfaces, which can effectively tune the activation barriers towards facilitating the oxygen evolution process. This work provides new insight into the design of heterostructure materials for advanced OER electrocatalysts. [ABSTRACT FROM AUTHOR]

With the strengths of zero carbon emission and high gravimetric energy density, hydrogen energy is recognized as a primary choice for future energy supply. Electrochemical water splitting provides a promising strategy for effective and sustainable hydrogen production through renewable electricity, and one of the immediate challenges toward its large‐scale application is the availability of low‐cost and efficient electrocatalysts for the hydrogen evolution reaction (HER). Given the enormous efforts in the exploration of potential transition‐metal carbide (TMC) electrocatalysts, this review aims to summarize the recent advances in synthetic methods and optimization strategies of TMC electrocatalysts. Additionally, the perspectives for the development of novel efficient TMC‐based catalysts are also proposed. [ABSTRACT FROM AUTHOR]

Transition-metal carbides (TMCs) have drawn broad attention as potential HER catalysts in recent years due to the platinum-like electron structure. Keywords: heteroatom doping; heterostructure; hydrogen evolution; transition-metal carbides EN heteroatom doping heterostructure hydrogen evolution transition-metal carbides 1 1 1 03/22/21 20210317 NES 210317 B Developing low-cost and highly active electrocatalysts b to replace Pt group metals is very critical to the hydrogen evolution reaction (HER). Heteroatom doping, heterostructure, hydrogen evolution, transition-metal carbides. [Extracted from the article]

Graphical abstract Highlights • OsP 2 nanoparticles anchored on N,P-doped carbon as new catalyst is synthesized. • The interaction between OsP 2 nanoparticles and carbon is good to the catalysis. • Hydrogen evolution reaction proceeds by Volmer-Heyrovsky mechanism in acid media. • This new electrocatalyst exhibits excellent HER activity at all PH values. Abstract Exploring hydrogen evolution reaction (HER) catalysts with high activity over the wide range of pH (0–14) is of great significance, but extremely challenging. Noble-metal phosphides are newly developed electrocatalysts that can function well at all pH values. Despite the pivotal role Os compounds have played in the progress of catalytic chemistry, its phosphides have never been demonstrated to mediate the HER. Herein, we report a new OsP 2 -based electrocatalyst that consists of fine OsP 2 nanoparticles (NPs) dispersed over N,P co-doped carbon film (OsP 2 @NPC) using a combination of template and pyrolysis methods. Impressively, this novel OsP 2 @NPC exhibits improved HER activity compared with Os@NPC, with small overpotentials of 38, 54, and 70 mV at 10 mA cm−2 and Tafel slopes of 40, 82, and 67 mV dec−1, and better stability than commercial Pt/C in 0.5 M H 2 SO 4 , 1.0 M phosphate buffer solution, and 1.0 M KOH, respectively. The experimental and computational results indicate that both the unique structure of the porous interconnected network and the interaction between OsP 2 NPs and NPC contribute to the robust activity. Meanwhile, the ∼40 mV dec−1 Tafel slope in 0.5 M H 2 SO 4 and the density functional theory (DFT) calculations suggest the predominant Volmer-Heyrovsky mechanism for the OsP 2 -catalyzed HER, with electrochemical desorption of hydrogen as the rate-limiting step. This new electrocatalyst is expected to enlarge the growing family of transition metal phosphides for the HER. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Co 1.11 Te 2 /C nanostructure was synthesized via a CVD method for the first time. • The N-doped carbon framework is contributed to improve the HER performance. • The Co 1.11 Te 2 /C exhibits the better HER activity, compared with CoTe/C and CoTe 2 /C. • Component control is a significant method to improve the HER performance. Abstract Rational structure design and component-controlled synthesis are attractive and challenging methods to develop materials with unique function for renewable energy conversion such as hydrogen production via water splitting. The earth-abundant and affordable transition metals have been regarded as ideal alternatives to precious platinum. Herein, we report the designed synthesis of component-modified cobalt telluride nanoparticles encapsulated in the nitrogen-doped carbon frameworks with the feature of high surface area and great electron conductivity. Compared with CoTe 2 /C and CoTe/C, the Co 1.11 Te 2 /C presents the highest catalytic activity for HER in 1M KOH due to its structural and component advantages. After a continuous reaction for 20 h or cycling for 1000 cycles, Co 1.11 Te 2 /C shows only a little performance loss. This work provides an effective approach to synthesize low-cost and efficient electrocatalysts for HER via rational structural and component design. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel 3D Mo 2 C@MoS 2 nanostructure with sulphur vacancies has been synthesized for HER. • The material delivers outstanding tafel slopes and overpotentials of pH 0–14. • The excellent performance is attributed to specific surface area, electronic interaction and active sites. • The 3D Mo 2 C@MoS 2 NS with SVs could lower the Gibbs free energy of atomic hydrogen (△G H*). Abstract It is essential but still a great challenge to improve the property of non-precious Hydrogen Evolution Reaction (HER) catalysts at all pH values to meet the vast energy demands even though much progress has been made in this field. Herein, an enhanced HER catalyst, non-noble-metal three-dimensional Mo 2 C@MoS 2 heterojunction nanostructure with high concentration of sulphur vacancies (3D Mo 2 C@MoS 2 NS) has been synthesized via multistep annealing in Ar atmosphere. The unique 3D Mo 2 C@MoS 2 NS delivers excellent HER performances over a wide range of pH 0–14, with Tafel slopes of 37, 46, and 39 mV dec−1 and overpotentials of 67, 121, and 86 mV at −10 mA cm−2 in 0.5 M H 2 SO 4 , 1 M PBS and 1 M KOH as well as continuous durability above 120 h, which are better than that of partial reported carbide, phosphide and selenide electrocatalysts. The excellent performance is attributed to high specific surface area, strong electronic interaction and abundant active sites. Besides, the density functional theory further indicates that the 3D Mo 2 C@MoS 2 NS could lower the Gibbs free energy of H adsorption (△G H*), leading to increased HER performance. Thus the 3D Mo 2 C@MoS 2 NS as an all-pH HER catalyst makes a major breakthrough in hydrogen evolution. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Atomic-layered graphene is synthesized by chemical vapor deposition. • The epitaxial graphene on the special surface of V 8 C 7 is synthesized for HER. • The electronic interactions between V 8 C 7 and graphene could improve HER activity. • The high activity and stability of material are existed in acid and alkaline media. Abstract Exploring low-cost, non-noble hydrogen evolution reaction (HER) catalysts with remarkable activity in both acidic and alkaline media still remains an enormous challenge. Herein, a novel V 8 C 7 NMs/GR heterogeneous catalyst has been synthesized by epitaxial growth of graphene as efficient acidic and alkaline HER electrocatalyst, for the first time. Electrochemical tests and DFT calculations indicate that high-activity of the exposed facet and low barrier energy for hydrogen adsorption and water dissociation could facilitate hydrogen evolution reaction. Owing to the electronic interactions between V 8 C 7 and graphene at active hybrid interfaces, this catalyst shows high HER activity with a low overpotential at 10 mA cm−2 (156 mV in 1 M KOH and 52 mV in 0.5 M H 2 SO 4), a small Tafel slope (89.4 mV dec−1 in 1 M KOH and 48.3 mV dec−1 in 0.5 M H 2 SO 4), and preferable durability in both acidic and alkaline media. This work opens up a new avenue for the epitaxial growth of graphene and exploring new-type active heterogeneous catalysts with advanced performance for HER. [ABSTRACT FROM AUTHOR]

• A series of RhP*x@NPC catalysts were developed by the combination of tunable morphology and controllable structure. • The ratios of Rh to P may be gradually tuned to achieve the optimum product that exhibits best catalytic activity. • DFT calculations suggest that the electrocatalytic activities can be greatly meliorated by introducing of P into Rh lattice. • The new Rh 2 P@NPC exhibits excellent NRR activity. Constructing high-efficient and cost-saving catalysts for electrochemical nitrogen reduction reaction (NRR) under ambient conditions is of great significance, but quite challenging. Herein, a series of foam-like composites comprised of small RhP x nanoparticles (NPs) and N, P co-doped carbon (NPC) framework are first reported as novel high-efficiency NRR electrocatalysts. Interestingly, the electronic structure and catalytic behavior of RhP x are modified by altering the contents of P in composites. Density function theory (DFT) calculations prove that the introduction of P into the rhodium lattice can dramatically reduce the catalytic reaction barrier and facilitate the intermediate process of catalytic reaction. Compared with most of the reported materials, this new catalyst possesses high ammonia (NH 3) yield rate of 37.6 μg h−1 mg cat. -1 and Faraday efficiency (FE) of 7.64 %, as well as good selectivity and superior stability in acid conditions. This work provides a theoretical basis and practical scheme for the wide application of other robust transition metal phosphides electrocatalysts in NRR. [ABSTRACT FROM AUTHOR]

• The novel Re 3 P 4 @NPVC and Re 2 P@NPVC catalysts were designed by a novel strategy. • Coupling metal Re and P is able to promote the HER pathway. • The electronic coupling of NPVC layer and nanoparticles efficiently promotes the electron-transfer process for HER. • The Re 3 P 4 @NPVC exhibit remarkable catalytic activity for HER at all pH, which rivals the commercial Pt/C. Considering the great application prospect of noble metal rhenium (Re) in the catalytic field derived from its intrinsic properties, exploring more novel and highly effective Re-based catalysts becomes an important topic. Herein, for the first time, we design a novel strategy for fabrication of Re 2 P and Re 3 P 4 nanoparticles anchored in N, P doped vesicular carbon (NPVC) via pyrolyzing ammonium perrhenate (NH 4 ReO 4), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and melamine on the surface of SiO 2 spheres. Choosing hydrogen evolution as a probe reaction, Re 3 P 4 @NPVC heterostructure exhibits highly efficient catalytic activity compared with as-synthesized samples, which rivals the commercial Pt/C. Concretely, the Tafel slope is 38, 77 and 62 mV dec−1, and overpotential is 40, 70 and 61 mV at 10 mA cm−2 in 0.5 M H 2 SO 4 , 1 M phosphate buffer solution and 1 M KOH, respectively. Both experiment and DFT calculation unambiguously validate that Coupling metal Re and P is able to promote the HER pathway by tuning the ΔG H* value close to the optimum, balancing adsorption and desorption of hydrogen. Besides, the electronic coupling of NPVC layer and NPs synergistically enhances the proton adsorption and reduction kinetics. [ABSTRACT FROM AUTHOR]