Plasma-coupled photocatalytic CO2/H2O conversion to tunable syngas over CuxPdy/TiO2 with electronic modulation

Photocatalytic conversion of CO2 and H2O into syngas provides a sustainable route for carbon utilization, but is limited by inefficient CO2 activation, rapid charge recombination, and the competing hydrogen evolution reaction. Herein, we report a P2CR (Plasma-coupled Photocatalytic CO2 Reduction) system based on electronically modulated CuxPdy/TiO2 for efficient and tunable syngas production. The optimized Cu11Pd1/TiO2 catalyst achieves a CO production of 54.66 mmol g-1 h-1 under plasma–light conditions, compared with 32.2 mmol g-1 h-1 under plasma-only operation, while only trace CO is detected under light-only photocatalytic conditions. The H2/CO ratio can be widely tuned from 0.05:1 to 6.13:1 by regulating the H2O content, Ar/CO2 ratio, and discharge power. Both experimental and theoretical results suggest that enhanced activity arises from the cooperation between plasma-assisted CO2 activation and photocatalytic conversion. The plasma facilitates CO2 activation, while the metal–support interface promotes electron transfer and favours the key steps associated with *COOH formation and H2O-derived *H generation. This synergistic coupling of plasma activation and interfacial electronic modulation enables efficient and composition-controllable syngas synthesis from CO2 and H2O under mild conditions.