MoS becomes an efficient and durable nonprecious-metal electrocatalyst for the hydrogen evolution reaction (HER) when it contains multifunctional active sites for water splitting derived from 1T-phase, defects, S vacancies, exposed Mo edges with expanded interlayer spacings. In contrast to previously reported MoS -based catalysts targeting only a single or few of these characteristics, the all-in-one MoS catalyst prepared herein features all of the above active site types. During synthesis, the intercalation of in situ generated NH molecules into MoS sheets affords ammoniated MoS (A-MoS ) that predominantly comprises 1T-MoS and exhibits an expanded interlayer spacing. The subsequent reduction of A-MoS results in the removal of intercalated NH and H S to form an all-in-one MoS with multifunctional active sites mentioned above (R-MoS ) that exhibits electrocatalytic HER performance in alkaline media superior to those of all previously reported MoS -based electrocatalysts. In particular, a hybrid MoS /nickel foam catalyst outperforms commercial Pt/C in the practically meaningful high-current region (>25 mA cm ), demonstrating that R-MoS -based materials can potentially replace Pt catalysts in practical alkaline HER systems.

Sulfur and nitrogen dual-doped molybdenum phosphides (MoP/SN) are synthesized via a (thio)­urea-phosphate-assisted strategy in which the reductant (thio)­urea acts as S and N source and phosphoric acid provides the P atom. The MoP/SN nanoparticles are generated by in situ phosphidation of indigenously synthesized ammonium phosphate-coated P-doped MoS x nanoparticles in a hydrogen atmosphere. Then, MoP/SN is anchored on graphene to obtain a hybrid electrocatalyst (MoP/SNG) that exhibits high activity and stability for electrochemical hydrogen evolution from water in both acidic and basic electrolytes, outperforming most MoP-based electrocatalysts reported in the literature. The dual doping and hybridization with graphene enhance electron conductivity of MoP and stabilize small MoP nanoparticles to increase activity and stability, especially in acid electrolytes.

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2D molybdenum disulfide (MoS2) displays a modest hydrogen evolution reaction (HER) activity in acidic media because the active sites are limited to a small number of edge sites with broader basal planes remaining mostly inert. Here, it is reported that the MoS2 basal planes could be activated by growing nickel phosphide (Ni2P) nanoparticles on them. Thus a Ni2P/MoS2 heterostructure is constructed via in situ phosphidation of an indigenously synthesized NiMoS4 salt as a single precursor to form a widely cross‐doped and chemically connected heterostructure. The conductivity and stability of the Ni2P/MoS2 heterostructure are further enhanced by hybridization with conductive N‐doped carbon supports. As a result, the Ni2P/MoS2/N:RGO or Ni2P/MoS2/N:CNT electrocatalyst displays Pt‐like HER performance in acidic media, outperforming the incumbent best HER electrocatalyst, Pt/C, in a more meaningful high current density region (>200 mA cm−2) making them a promising candidate for practical water electrolysis applications. Since nonprecious metal catalysts showing Pt‐like HER performance in acidic media are rare, the Ni2P/MoS2 heterostructure catalyst is a promising candidate for practical hydrogen production via water electrolysis.

Boron-and nitrogen-codoped molybdenum carbide nanoparticles imbedded in a B,N-doped carbon network (B,N:Mo 2 C@BCN) have been synthesized as a noble-metal-free hybrid electrocatalyst via an eco-friendly organometallic complex of Mo imidazole and boric acid. When it is used as a bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an aqueous alkaline solution, the B,N:Mo 2 C/BCN catalyst displays high activity and stability in basic electrolytes, better than those of noble-metal-based Pt/C and IrO 2 and previously reported transition metal carbide based electrocatalysts. The mechanistic study reveals that the enhanced performance of the hybrid material is attributable to the improved charge transfer characteristics as well as increased active surface areas owing to its modified electronic structure by B and N codoping and formation of tiny nanoparticles imbedded in BCN networks. The synthesis approach employed in this study could also be suitable for tuning properties of other transition-metal carbides for use as electrocatalysts.

Developing efficient and durable electrocatalysts is key to optimizing the electrocatalytic hydrogen evolution reaction (HER), currently one of the cleanest and most sustainable routes for producing hydrogen. Here, a unique and efficient approach to fabricate and embed uniformly dispersed Ir nanoparticles in a 3D cage‐like organic network (CON) structure is reported. These uniformly trapped Ir nanoparticles within the 3D CON (Ir@CON) effectively catalyze the HER process. The Ir@CON electrocatalyst exhibits high turnover frequencies of 0.66 and 0.20 H2 s−1 at 25 mV and small overpotentials of 13.6 and 13.5 mV while generating a current density of 10 mA cm−2 in 0.5 m H2SO4 and 1.0 m KOH aqueous solutions, respectively, as compared to commercial Pt/C (18 and 23 mV) and Ir/C (20.7 and 28.3 mV). More importantly, the catalyst shows superior stability in both acidic and alkaline media. These results highlight a potentially powerful approach for the design and synthesis of efficient and durable electrocatalysts for HER.

Five phases of molybdenum carbide encapsulated by a boron–carbon–nitrogen (BCN) network are synthesized by decomposition of a Mo–imidazole-borate organometallic complex with slight variations in the imidazole-borate ligand structure.

Metallic dicobalt phosphide (Co 2 P) is doped with electronegative sulfur (S:Co 2 P) by using an economical and eco-friendly thiourea-phosphate-assisted strategy. Density functional theory calculation in conjunction with X-ray photoelectron spectroscopy reveals that S-doping decreases the electron density near the Fermi level to reduce the metallic nature of Co 2 P. Thus, a more positive charge is induced onto Co to balance between hydride (Co δ+ H δ− ) and proton (S/P δ− H δ+ ) acceptors. As a result, it increases the number of active Co 2+ sites as well as the turnover frequency of a single site. The hybrid electrodes obtained by loading S:Co 2 P nanoparticles on N-doped carbon cloth or nickel foam (NF) exhibit an outstanding activity and stability of hydrogen and oxygen evolution reactions in alkaline electrolytes outperforming conventional, precious metal-based Pt/C and IrO 2 catalysts, and most of the other state-of-the-art nonprecious metal electrocatalysts reported so far. An alkaline electrolyzer with S:Co 2 P@NF as both cathode and anode produces a stable current density of 100 mA/cm 2 at 1.782 V, which is superior to the IrO 2 −Pt/C electrolyzer (1.823 V).