The hydrogen evolution reaction (HER) of molybdenum disulfide (MoS₂) is limited in alkaline and acid solution because the active sites are on the finite edge with extended basal plane remaining inert. Herein, we activated the interfacial S sites by coupling with Ru nanoparticles on the inert basal plane of MoS₂ nanosheets. The density functional theory (DFT) calculation and experimental results show that the interfacial S electronic structure was modulated. And the results of ∆G_H* demonstrate that the adsorption of H on the MoS₂ was also optimized. With the advantage of interfacial S sites activation, the Ru-MoS₂ needs only overpotential of 110 and 98 mV to achieve 10 mA·cm^–2 in both 0.5 M H₂SO₄ and 1 M KOH solution, respectively. This strategy paves a new way for activating the basal plane of other transition metal sulfide electrocatalysts for improving the HER performance.

The ordered Pt-based intermetallic nanoparticles (NPs) with small size show superior magnetic or catalytic properties, but the synthesis of these NPs still remains a great challenge due to the requirement of high temperature annealing for the formation of the ordered phase, which usually leads to sintering of the NPs. Here, we report a simple approach to directly synthesize monodisperse ordered L1₀-FePt NPs with average size 10.7 nm without further annealing or doping the third metal atoms, in which hexadecyltrimethylammonium chloride (CTAC) was found to be the key inducing agent for the thermodynamic growth of the Fe and Pt atoms into the ordered intermetallic structure in the synthetic process. In particular, 10.7 nm L1₀-FePt NPs synthesized by the proper amount of CTAC show a coercivity of 3.15 kOe and saturation magnetization of 45 emu/g at room temperature. The current CTAC-assisted synthetic strategy makes it possible to deeply understand the formation of the ordered Pt-based intermetallic NP in solution phase synthesis.

The morphology and size of Pt-based bimetallic alloys are known to determine their electrocatalytic performance in reactions relevant to fuel cells. Here, we report a general approach for preparing Pt-M (M = Fe, Co and Ni) bimetallic nano-branched structure (NBs) by a simple high temperature solution-phase synthesis. As-prepared Pt-M NBs show a polycrystalline structure and are rich in steps and kinks on the surface, which promote them favorable bifunctional catalytic properties in acidic electrolytes, specifically in terms of the oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR). Specially, Pt-Co NBs/C catalyst shows 6.1 and 5.3 times higher in specific activity (SA) and mass activity (MA) for ORR than state-of-the-art commercial Pt/C catalysts, respectively. Moreover, it exhibits a loss of 4.0% in SA and 14.4% in MA after 10,000 cycles of accelerated durability tests (ADTs) compared with the initial activities. In addition, we also confirmed the superior MOR activity of Pt-Co NBs/C catalyst in acidic electrolytes. For Pt-M NBs with other alloying metals, the ORR and MOR activities are both higher than commercial catalysts and are in the sequence of Pt-Co/C > Pt-Fe/C > Pt-Ni/C > commercial Pt/C (or PtRu/C). The improved activities and durability can benefit from the morphological and compositional effects. This synthesis approach may be applied to develop bifunctional catalysts with enhanced ORR and MOR properties for future fuel cells designs.

The electrocatalytic hydrogen evolution reaction (HER) is one of the most promising ways for low-cost hydrogen production in the future. In this work, hetero S atoms were introduced into the MoO₂ to enhance the catalytic activity by simultaneously adjusting electron structure, engineering lattice defect, and increasing oxygen vacancies. And the S doped MoO₂ nanosheets with proper S doping amount show the enhanced performance for HER. The optimized catalyst shows a small onset overpotential as low as 120 mV, a low overpotential of 176 mV at the current density of 10 mA/cm² which is decreased 166 mV compared to that of the pristine MoO₂ nanosheets, a low Tafel slope of 57 mV/decade, and a high turnover frequency of 0.13 H₂/s per active site at 150 mV. This finding proposes an effective strategy to prepare nonprecious metal oxide catalyst for enhancing HER performance by rationally doping hetero atoms.