Electrochemical characterization and photocatalytic activity of MBiO3 (M = K and Na) for hydrogen production

•Pentavalent bismuth oxides have a favorable electronic structure for photocatalytic process.•KBiO3 and NaBiO3 have a wide optical absorption allows the activation in both UV and visible regions.•KBiO3 and NaBiO3 fulfill the condition of overpotentials for photocatalytic water splitting.•Photocatalytic activity can be mainly attributed to the electroactive area of the semiconductor.•A hydrogen production rate of 71. μmol·g−1·h−1 was obtained with KBiO3 o and 33.8 μmol·g−1·h−1 with NaBiO3.