Journal Article defect engineering Mg3(Sb,Bi)2 MoSe2 amorphous domains black titanium dioxide charge separation disorder electrocatalysis electron correlation electronic phase transitions electronic structure hydrogen doping hydrogen-evolution reaction (HER) lattice thermal conductivity oxygen vacancies perovskite oxides phase photocatalytic nitrogen fixation rare-earth nickelates single-unit-cell Bi3O4Br thermoelectric materials