In this study, phosphorus doped graphene supported PtNiP nanocluster electrocatalyst (PtNiP/P-graphene) was successfully prepared via a simple hypophosphite-assisted co-reduction method. The improved anchoring force and increased anchoring sites of graphene support result from phosphorus doping as well as size-confined growth effect of NaH₂PO₂ leads to uniform dispersion of ultrafine PtNiP nanoclusters. Doped P also promotes the removal of CO-like intermediate by adjusting Pt electronic structure combining with alloyed Ni via electronic effects. As a result, the as-prepared PtNiP/P-graphene catalyst with more exposed active sites and optimized electronic structure of Pt alloy shows excellent electrocatalytic performances for methanol oxidation reaction (MOR) both in activity and durability in an acidic medium.

Although Sn-based catalysts have recently achieved considerable improvement in selective electro-catalyzing CO₂ into HCOOH, the role of various valence Sn species is not fully understood due to the complexity and uncertainty of their evolution during the reaction process. Here, inspired by the theoretical simulations that the concomitant multivalent Sn (Sn⁰, Sn^II and Sn^IV) can significantly motivate the intrinsic activity of Sn-based catalyst, the Sn/SnO/SnO₂ nanosheets were proposed to experimentally verify the synergistic effect of multivalent Sn species on the CO₂-into-HCOOH conversion. During CO₂ reduction reaction, the Sn/SnO/SnO₂ nanosheets, which are prepared by the sequential hydrothermal reaction, calcined crystallization and low-temperature H₂ treatment, exhibit a high FE_HCOOH of 89.6% at -0.9 V_RHE as well as a large cathodic current density. Systematic experimental and theoretical results corroborate that multivalent Sn species synergistically energize the CO₂ activation, the HCOO* adsorption, and the electron transfer, which make Sn/SnO/SnO₂ favour the conversion from CO₂ into HCOOH in both thermodynamics and kinetics. This proof-of-concept study establishes a relationship between the enhanced performance and the multivalent Sn species, and also provides a practicable and scalable avenue for rational engineering high-powered electrocatalysts.

A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co₃O₄ nanosheets (PtCo/Co₃O₄ NSs) supported on Ni foam. The prepared nanomaterial is used as an electrocatalyst for NaBH₄ oxidation in alkaline solution. The morphology and phase composition of PtCo/Co₃O₄ NSs are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The catalytic performance of PtCo/Co₃O₄ NSs is investigated by cyclic voltammetry (CV) and chronoamperometry (CA) in a standard three-electrode system. Current densities of 70 and 850 mA·cm^–2 were obtained at–0.4 V for Co/Co₃O₄ and PtCo/Co₃O₄ NSs, respectively, in a solution containing 2 mol·L^–1 NaOH and 0.2 mol·L^–1 NaBH₄. The use of a noble metal (Pt) greatly enhances the catalytic activity of the transition metal (Co) and Co₃O₄. Besides, both Co and Co₃O₄ exhibit good B–H bond breaking ability (in NaBH₄), which leads to better electrocatalytic activity and stability of PtCo/Co₃O₄ NSs in NaBH₄ electrooxidation compared to pure Pt. The results demonstrate that the as-prepared PtCo/Co₃O₄ NSs can be a promising electrocatalyst for borohydride oxidation.