Intercalation Effect in NiAl-layered Double Hydroxide Nanosheets for CO2 Reduction Under Visible Light

Photocatalytic reduction of CO2(CO2PR)to valuable solar fuels is considered as a promising route to the amelioration of fossil fuel conundrum and the mitigation of greenhouse gases.Although progress has been made to enhance CO2PR performance,the available method that can promote the selectivity of CO2PR products remains to be a challenge.In this work,we synthesized NO3-or CO32-intercalated NiAl-layered double hydroxide(NiAl-LDH)photocatalysts and investigated the performance of CO2PR in the presence of an electron donor and a photosensitizer.Compared with Ni2Al-CO32-,Ni2Al-NO3-exhibited superior catalytic performance in the CO2PR,and the resulted selectivity of CH4 in Ni2Al-NO3-(6.1%)was 12.2 times that of Ni2Al-CO32-(0.5%)under visible light irradiation.X-Ray absorption fine structure(XAFS)result reveals a relative abundance of defects in Ni2Al-NO3-,which played as active sites and promoted charge transfer in CO2PR for the efficient CH4 evolution.

Photocatalytic syngas synthesis from CO_(2) and H_(2)O using ultrafine CeO_(2)-decorated layered double hydroxide nanosheets under visible-light up to 600 nm

The rational design of photocatalyst that can effectively reduce CO_(2) under visible light(l>400 nm),and simultaneously precise control of the products syngas(CO/H2)ratio is highly desirable for the Fischer-Tropsch reaction.In this work,we synthesized a series of CeO_(2)-decorated layered double hydroxides(LDHs,Ce-x)samples for photocatalytic CO_(2) reduction.It was found that the selectivity and productivity of CO and H_(2) from photoreduction of CO_(2) in conjunction with Ru-complex as photosensitizer performed an obvious“volcano-like”trend,with the highest point at Ce-0.15 and the CO/H_(2) ratio can be widely tunable from 1/7.7 to 1/1.3.Furthermore,compared with LDH,Ce-0.15 also drove photocatalytic CO_(2) to syngas under 600 nm irradiation.It implied that an optimum amount of CeO_(2) modifying LDH promoted the photoreduction of CO_(2) to syngas.This report gives the way to fully utilize the rare earth elements and provides a promising route to enhance the photo-response ability and charge injection efficiency of LDH-based photocatalysts in the synthesis of syngas with a tunable ratio under visible light irradiation.