International Research Center for Renewable Energy;
State Key Laboratory of Multiphase Flow in Power Engineering;
Xi'an Jiaotong University;
Xi'an 710049;
P.R.China;
Department of Physics;
Tamkang University;
New Taipei City 25137;
Taiwan;
P.R.China;
Institute of Physics;
Chinese Academy of Sciences;
Beijing 100190;
P.R.China;
Photocatalytic hydgogen evolution; Single metal atom; Polymeric carbon nitride;