Bi9P2O18Cl: Phase Transition and Hydrogen Production by Photocatalytic Water-Splitting

Bi9P2O18Cl crystals were prepared by the high-temperature molten salt method. Single-crystal X-ray diffraction data analyses demonstrated that Bi9P2O18Cl can undergo a crystal-to-crystal phase transition from room temperature to low temperature. At room temperature, this compound (alpha-phase) crystallizes in monoclinic space group P2(1)/m (11) with unit cell parameters a=1.149 10(7) nm, b=0.540 64(4) nm, c=1.463 69(9) nm, beta=93.741(6)degrees, V= 0.907 38(10) nm(3). And at 100 K, it (beta-phase) crystallizes in monoclinic space group P21/n (14) with unit cell parameters a=1.790 56(4) nm, b=0.538 870(10) nm, c=1.915 57(4) nm, beta=103.693(2)degrees, V=1.795 76(6) nm(3). Additionally, high pure powder samples of Bi9P2O18Cl were synthesized using solid-state reaction method, which exhibited promising performance in photocatalytic water splitting to produce H-2, the H-2 evolution rates reached 33.69 mu mol.g(-1).h(-1). CCDC: 2128785, alpha-phase Bi9P2O18Cl; 2145491, beta-phase Bi9P2O18Cl.