National Synchrotron Radiation Laboratory Innovation Center of Chemistry for Energy Materials of Science and Technology of China 230029;
Hefei National Laboratory for Physical Science at the Microscale and Department of Chemical Physics Innovation Center of Quantum Information and Quantum Physics of Science and Technology of China 230026;
School of Chemistry and Chemical Engineering University 230601;
School of Physical Science of Chinese Academy of Sciences 100049;
Valence states regulation; CrO_(x)cocatalyst; Lower-energy irradiation; Photocatalytic CO_(2)reduction; High CH_(4)selectivity;