A solvent-free strategy for synthesis of Co9S8 nanoparticles entrapped, N, S-codoped mesoporous carbon as hydrogen evolution electrocatalyst

Lacunary polyoxometalate oriented construction of dispersed Ni3S2 confined in WO3 for electrocatalytic water splitting

Manufacturing low-cost, high-performance and earth-rich catalysts for hydrogen evolution (HER) and oxygen evolution reactions (OER) is critical to achieving sustainable green hydrogen production. Herein, we utilize lacunary Keggin-structure [PW₉O₃₄]^9- (PW₉) as a molecular pre-assembly platform to anchor Ni within a single PW₉ molecule by vacancy-directed and nucleophile-induced effects for the uniform dispersion of Ni at the atomic level. The chemical coordination of Ni with PW₉ can avoid the aggregation of Ni and favor the exposure of active sites. The Ni₃S₂ confined by WO₃ prepared from controlled sulfidation of Ni₆PW₉/Nickel Foam (Ni₆PW₉/NF) exhibited excellent catalytic activity in both 0.5 M H₂SO₄ and 1 M KOH solutions, which required only 86 mV and 107 mV overpotentials for HER at a current density of 10 mA∙cm^-2 and 370 mV for OER at 200 mA∙cm^-2. This is attributed to the good dispersion of Ni at the atomic level induced by trivacant PW₉ and the enhanced intrinsic activity by synergistic effect of Ni and W. Therefore, the construction of active phase from the atomic level is insightful to the rational design of dispersed and efficient electrolytic catalysts.

Interfacial effect of Co4S3–Co9S8 nanoparticles hosted on rGO sheets derived from molecular precursor pyrolysis on enhancing electrochemical behaviour

Co₄S₃–Co₉S₈ nanoparticles with abundant interfaces hosted on reduced graphene oxide were synthesized via a monomolecular pyrolysis strategy to boost catalytic activity.