Photo-to-Thermal Conversion Harnessing Low-Energy Photons Renders Efficient Solar CO Reduction

Efficient photocatalytic solar CO reduction presents a challenge because visible-to-near-infrared (NIR) low-energy photons account for over 50% of solar energy. Consequently, they are unable to instigate the high-energy reaction necessary for dissociating C═O bonds in CO. In this study, we present a novel methodology leveraging the often-underutilized photo-to-thermal (PTT) conversion. Our unique two-dimensional (2D) carbon layer-embedded MoC (MoC-C) MXene catalyst in black color showcases superior near-infrared (NIR) light absorption. This enables the efficient utilization of low-energy photons via the PTT conversion mechanism, thereby dramatically enhancing the rate of CO photoreduction. Under concentrated sunlight, the optimal MoC-C catalyst achieves CO reduction reaction rates of 12000-15000 μmol·g·h to CO and 1000-3200 μmol·g·h to CH. Notably, the catalyst delivers solar-to-carbon fuel (STF) conversion efficiencies between 0.0108% to 0.0143% and the STF = 0.0123%, the highest recorded values under natural sunlight conditions. This innovative approach accentuates the exploitation of low-frequency, low-energy photons for the enhancement of photocatalytic CO reduction.