Efficient photocatalytic hydrogen production over La/Rh co-doped Ruddlesden-Popper compound Sr2TiO4

La/Rh can be successfully co-doped into Sr2TiO4 at a synthesis temperature as low as 900 °C. The presence of Rh inside Sr2TiO4 greatly improves its visible light absorbance and photocatalytic activity while co-doping La helps to build a charge compensated system. The origin of visible light absorption and photocatalytic activity stems from a newly formed valence band with mainly Rh 4d character inside the band gap of Sr2TiO4.