Interfacial Synthesis of Cs 2 PtCl 6 Perovskite for Strong Coupling with V 4 C 3 T x MXene Toward Efficient Hydrogen Evolution and Urea Oxidation

Abstract A key innovation in this work is the development of a trapping method to synthesize perovskite Cs 2 PtCl 6 nanoparticles at a liquid–liquid interface under ambient conditions. The resulting nanoscale Cs 2 PtCl 6 particles are able to combine with various MXenes via PtCl 6 2− units, among which V 4 C 3 T X MXene forms strongly coupled Cs 2 PtCl 6 @V 4 C 3 T X composites. Cs 2 PtCl 6 @V 4 C 3 T X exhibits excellent hydrogen evolution reaction (HER), delivering a dramatically reduced overpotential of ∼39 mV a current density of 10 mA cm − 2 , which outperforms the pristine V 4 C 3 T X , Cs 2 PtCl 6 , and other Cs 2 PtCl 6 @MXenes composites investigated. On the other hand, Cs 2 PtCl 6 @V 4 C 3 T X exhibits negligible oxygen evolution reaction, but remarkably high‐performance urea oxidation reaction. The selective anodic reactivity simultaneously reduces the overall energy input required for HER. Comprehensive studies with other MXenes and their Cs 2 PtCl 6 hybrids highlight the unique and critical role of V 4 C 3 T X in facilitating electron transfer and catalytic stability, paving the way for simultaneous production of clean energy and remediation of organic pollutants.