Porous　ZnGa2O4　microspheres　(P-ZGO)　are　synthesized　by　a　facial　glucose-mediated　microwave　hydrothermal　method　followed　by　annealing.　The　morphological,　photoelectric　and　photocatalytic　properties　of　the　as-prepared　P-ZGO　sample　are　characterized　in　detail,　and　the　results　show　that　the　P-ZGO　photocatalyst　has　a　good　crystallinity,　large　species　surface　area,　hierarchical　mesoporosity,　and　distinguished　photoelectric　properties.　Under　254　nm　UV　irradiation,　the　P-ZGO　sample　shows　a　much　higher　activity　and　stability　than　TiO2　in　the　photocatalytic　degradation　of　gas-phase　aromatic　pollutants.　The　average　conversion　efficiencies　of　toluene　and　benzene　over　P-ZGO　are　~56.6%　and　~44.3%,　and　with　corresponding　mineralization　rates　of　~86.3%　and　~65.2%,　respectively.　No　remarkable　deactivation　of　P-ZGO　is　observed　in　a　60　h　heterogeneous　photoreaction.　Furthermore,　the　as-prepared　P-ZGO　sample　also　shows　an　excellent　photocatalytic　efficiency　(up　to　99.8%)　for　the　liquid-phase　As(III)　removal　from　water.　The　distinguished　photocatalytic　performance　of　P-ZGO　can　be　ascribed　to　its　unique　electronic　structures　and　hierarchical　morphologies.　According　to　the　results　of　our　analysis,　a　possible　mechanism　is　also　proposed　to　elaborate　the　photocatalytic　oxidation　process　in　the　pollutants/P-ZGO　system.　©　2019　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.