Rational design of electrochemical sulfide oxidation reaction (SOR) catalysts is a prerequisite to fully recycling hydrogen (H₂) and elemental sulfur (S⁰) resources, realizing the bridge between environment and energy fields, as well as enlightening the optimization of metal‒sulfur battery applications. While transition metal catalysts often suffer from sulfur poisoning, single-atom catalysts (SACs) offer a promising solution, where the precise coordination environment of metal centers becomes a critical determinant of catalytic performance. Herein, for the first time, we develop a Ni single-atom catalyst for SOR with unique Ni-N₃O₁ coordination anchored on hierarchically porous carbon (Ni₁@HPC), which demonstrates remarkable advantages over conventional Ni-N₄ or Ni-O₄ configurations, exhibiting a superior SOR activity (0.37 V vs. RHE at 100 mA·cm⁻²) that surpasses reported carbon-based catalysts and is comparable to most metal-based catalysts. In situ Raman and density functional theory (DFT) results reveal that the HPC facilitates rapid product S⁰ desorption while the Ni-N₃O₁ coordination enables appropriate reactant sulfide (S²⁻) adsorption, striking a critical balance between activity and stability that other coordination geometries fail to achieve. Additionally, the practical application of coupling hydrogen evolution reaction (HER) and SOR is realized on Ni₁@HPC with low power consumption, which is a promising alternative to the traditional overall water splitting (OWS) process. This work not only establishes a structure–activity relationship for single-atom catalysts in SOR but also provides a general strategy for optimizing metal coordination in electrocatalytic systems.

Photocatalytic dehydrogenative homocoupling of benzyl derivatives is a green and sustainable strategy for the direct construction of C(sp³)–C(sp³) bonds. However, the efficiency of these reactions is significantly hindered by the poor surface kinetics of the hydrogen evolution reaction (HER) and severe charge recombination. Herein, we demonstrate that the electrostatic self-assembly of MoS₂ colloids on CdS nanosheets (MoS₂/CdS) can efficiently capture photogenerated electrons to drive H⁺ reduction, owing to their intrinsic excellent catalytic ability for HER and their strong electron-sink effect for charge separation. This, in turn, facilitates the migration of photogenerated holes from the bulk to the surface, enabling more holes to initiate the oxidative cleavage of C–H bonds in benzyl derivatives, such as cumene. More importantly, MoS₂ colloids, with Mo atoms sandwiched between two sulfur layers, exhibit much lower interaction with produced ·C(CH₃)₂Ph radicals compared to conventional HER cocatalysts, such as noble or transition metal co-catalysts. This facilitates the departure of the ·C(CH₃)₂Ph radicals for C(sp³)–C(sp³) homocoupling reactions, thus enhancing selectivity toward bicummyl. This work presents an efficient, green, and cost-effective strategy for the dehydrogenative homocoupling of benzyl derivatives to construct C(sp³)–C(sp³) bonds under mild conditions.