Single-atom catalysts (SACs), on account of their outstanding catalytic potential, are currently emerging as high-performance materials in the field of heterogeneous catalysis. Constructing a strong interaction between the single atom and its supporting matrix plays a pivotal role. Herein, Ti₃C₂T_x-MXene-supported Ni SACs are reported by using a self-reduction strategy via the assistance of rich Ti vacancies on the Ti₃C₂T_x MXene surface, which act as the trap and anchor sites for individual Ni atoms. The constructed Ni SACs supported by the Ti₃C₂T_x MXene (Ni SACs/Ti₃C₂T_x ) show an ultralow onset potential of −0.03 V (vs reversible hydrogen electrode (RHE)) and an exceptional operational stability toward the hydrazine oxidation reaction (HzOR). Density functional theory calculations suggest a strong coupling of the Ni single atoms and their surrounding C atoms, which optimizes the electronic density of states, increasing the adsorption energy and decreasing the reaction activation energy, thus boosting the electrochemical activity. The results presented here will encourage a wider pursuit of 2D-materials-supported SACs designed by a vacancy-trapping strategy. 

Solar-driven diluted CO₂ reduction is an alternative way to realize carbon neutrality, although promoting the photo-reactivity and selectivity in low CO₂ contents remains a great challenge. Herein, an atomically dispersed Cu catalyst in a compressive strained BiOCl substrate (Cu₁-BOC-CRS) is identified as a promising photocatalyst for diluted CO₂ reduction reaction, capable of producing CO without any sacrificial agents or sensitizers. The single Cu atoms and the local surface strain facilitate CO₂ adsorption, resulting in impressive CO formation rates of 122 and 99 μmol g^-1 h^-1 respectively under pure and diluted CO₂ conditions. Experimental investigations revealed that the occupation of single Cu atoms in the BiOCl extends the light absorbance and charge transfer, which in turn integrates the surface CO₂ capture and conversion. Moreover, the compressive strain provides an extra low-energy route towards CO₂-to-CO conversion, offering valuable insights for the future design of highly efficient photocatalysts for diluted CO₂ reduction.

The sluggish HER kinetics under alkaline conditions largely limit the development of alkaline water electrolysis. Decades of efforts have been reported to elucidate the origin of the pH dependence of HER kinetics and facilitate the alkaline HER kinetics. Apart from the widely concerned thermodynamic factors, the electrode process also depends unignorably on the kinetics of the electrochemical interface. Herein, we presented the facilitated HER kinetics by introducing porous amine cage-enabled confinement to Ptcatalyst to engineer the interface between the Pt surface and the aqueous electrolyte. In situ electrochemical surface-enhanced Raman spectra (SERS) measurements and ab initio molecular dynamics (AIMD) simulation jointly unveiled the fundamental interfacial interaction between water and cage that its -NH- moiety largely reduces the rigidity of the net of interfacial water H-bonds at negative HER potentials, which makes the net flexible enough to reorganize for better charge transfer. Our in-depth investigation pinpointed that the -NH- moiety acted as a proton pump and generated hydroxide transfer by forming and breaking H-bonds with interfacial water, refreshing the reactive water layer on the Pt surface. Our results address the crucial role of controllable interfacial kinetics during electrocatalytic reactions, and our strategy of establishing a soft-confining interfacial regulator offers a promising roadmap for manipulating electrocatalytic interfacial kinetics.

Electrochemical CO₂ reduction reaction (ECO₂RR) to produce valuable chemicals and fuels is a promising way to make use of excessive CO₂ as one of the major green-house gases debatably responsible for climate change. The chemically inert feature of CO₂ molecules makes the first-step elementary reaction with one electron reduction challenging in thermodynamics, leading to a high overpotential for this step and the overall ECO₂RR as well. Herein, we reported the successful fabrication of CO₂-philic PIL-modified Au model catalyst with enhanced ECO₂RR performance by a local CO₂ enrichment strategy. The modified gas diffusion electrode exhibited ~ 100% Faradaic efficiency for CO₂-to-CO conversion (FECO) in a wide potential window of -0.2 ~ -1.0 V (versus reversible hydrogen electrode. RHE) with pure CO₂ feeding, and notablymaintained the FECO > 90% even at a low CO₂ concentration of 20 % vol..