Fig. 4

Photo-coupled electrochemical and electrochemical reduction of CO2. a FECO on HNTM-Co-SA under visible light (red line)/dark (black line). b FEHCOO− on HNTM-Cu-SA under visible light (red line)/dark (black line). c TOF curves of HNTM-Co-SA under visible light (red line)/dark (black line). d TOF curves of HNTM-Cu-SA under visible light (red line)/dark (black line). Error bars are ± s.d.