Rh/InGaN1−xOx nanoarchitecture for light-driven methane reforming with carbon dioxide toward syngas

Abstract

Light-driven dry reforming of methane toward syngas presents a proper solution for alleviating climate change and for the sustainable supply of transportation fuels and chemicals. Herein, Rh/InGaN1−xOx nanowires supported by silicon wafer are explored as an ideal platform for loading Rh nanoparticles, thus assembling a new nanoarchitecture for this grand topic. In combination with the remarkable photo-thermal synergy, the O atoms in Rh/InGaN1−xOx can significantly lower the apparent activation energy of dry reforming of methane from 2.96 eV downward to 1.70 eV. The as-designed Rh/InGaN1−xOx NWs nanoarchitecture thus demonstrates a measurable syngas evolution rate of 180.9 mmol gcat−1 h−1 with a marked selectivity of 96.3% under concentrated light illumination of 6 W cm−2. What is more, a high turnover number (TON) of 4182 mol syngas per mole Rh has been realized after six reuse cycles without obvious activity degradation. The correlative 18O isotope labeling experiments, in-situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) and in-situ diffuse reflectance Fourier transform infrared spectroscopy characterizations, as well as density functional theory calculations reveal that under light illumination, Rh/InGaN1−xOx NWs facilitate releasing *CH3 and H+ from CH4 by holes, followed by H2 evolution from H+ reduction with electrons. Subsequently, the O atoms in Rh/InGaN1−xOx can directly participate in CO generation by reacting with the *C species from CH4 dehydrogenation and contributes to the coke elimination, in concurrent formation of O vacancies. The resultant O vacancies are then replenished by CO2, showing an ideal chemical loop. This work presents a green strategy for syngas production via light-driven dry reforming of methane.