Ni2O3-modified SrTiO3 for enhanced visible-light photocatalytic CO2 reduction activity

Abstract. Low-cost and effective cocatalyst Ni2O3 was loaded on SrTiO3 (STO) via a simple one-step hydrothermal method. The Ni2O3  /  SrTiO3  (  m  )   photocatalysts were systematically characterized and applied to visible-light-driven CO2 reduction to investigate their photocatalytic activity. The series of the Ni2O3-modified SrTiO3 photocatalysts presented an improved photocatalytic activity and stability. Here, the N5.4STO  (  m  )   catalyst showed the best photocatalytic activity, with CO and CH4 yielding up to 11.57 and 1.51  μmol  /  g, respectively, under visible-light irradiation of 3 h, which were 3.15 and 14.84 times higher than that of pure STO(m), respectively. Based on the characterization and experimental results, the enhanced photocatalytic activity might be attributed to the following reasons: (1) Ni2O3 well dispersed on SrTiO3 served as CO2 attachment sites; (2) the modification of Ni2O3 could red shift the absorption edge and broaden the visible-light response ability; and (3) Ni2O3 nanoparticles act as electron traps to capture photogenerated electrons, effectively blocking the recombination of electron–hole pairs. The work offers important insights into the design of non-noble metal oxide cocatalyst modified photocatalysts for electron capture and photoreduction.