NiO-boosted Nb2O5 photocatalyst for highly selective conversion of CO2 into CH4

Amidst the impending energy crisis and escalating concerns about global warming, photocatalytic reduction of carbon dioxide (CO2) emerges as a promising solution. However, the practical application of this technology has been hindered by challenges such as the poor photoresponse of existing photocatalysts toward visible light, inefficient separation efficiency of photoinduced electron-hole pairs, and subpar product selectivity. This work simultaneously addresses these limitations by enhancing the activity of photocatalytic CO2 reduction through the strategic incorporation of nickel oxide (NiO) onto niobium pentoxide (Nb2O5). In this study, Nb2O5 was prepared using the hydrothermal and calcination methods, culminating in the synthesis of NiO-supported Nb2O5 achieved through the photodeposition method. The resulting 2 %-NIONBO photocatalyst with the optimal loading of NiO exhibited a remarkable methane (CH4) production yield of 29.65 μmol/g/h, a striking 6.2-fold improvement over solitary NBO. In addition, the useful carbon monoxide (CO) fuel was also detected from the photoreduction of CO2, where 2 %-NIONBO exhibited a CO yield of 7.22 μmol/g/h, demonstrating a 3.4-fold enhancement over NBO, along with an outstanding CH4 selectivity of 80.42 %. This study provides insights into the design and development of Nb-based photocatalysts for significantly enhanced efficiency in photocatalytic CO2 reduction, paving the way for advancements in sustainable energy solutions and addressing environmental issues.