Intrinsic photocatalytic water reduction over PbGaBO4 comprising edge-sharing GaO6 chains.

Metal borates are well-known optical materials while their semiconducting behavior, i.e. photocatalytic property, was less studied. Inspired by the recent publications on gallium borates with good photocatalytic performances, we investigated photocatalytic water reduction activity of another gallium borate, PbGaBO 4 , comprising edge-sharing GaO 6 -chains. Both conventional and solution assisted solid state reaction methods were employed for the preparation. Phase purity and the crystallinity of both samples were identified by powder X-ray diffraction and scanning electron microscopy. The UV–Vis reflectance spectra suggested the wide bandgap characteristic (4.10 eV) and theoretical calculations pointed out that the 6s and 5p orbitals of Pb 2+ contribute to both the bottom of CB and the top of VB. However the ionic bonding of Pb O in PbGaBO 4 led to a slight hydrolysis during the photocatalysis process, which can be suppressed by loading cocatalysts of Pt and RuO x . In addition, such a surficial modification significantly improved the photocatalytic water reduction ability, with an optimal H 2 evolution rate of 41.9(9) μmol/h/g under UV-light irradiation. [ABSTRACT FROM AUTHOR]