Construction of Nitrogen-Doped Carbon Functionalized Ni(OH)2 for Selective CO2 Photoreduction

Photoreduction of CO2 is a sustainable way of producing carbon-neutral fuels. However, the development of robust catalyst for the selective reduction of CO2 to value-added chemicals remains a challenge. Using a photochemical approach, encapsulation of nitrogen-doped carbon and Ni(OH)(2) is to form a hybrid (Ni(OH)(2)/NC) for photocatalytic CO2 reduction. The as-synthesized Ni(OH)(2)/NC catalyst exhibits enhanced selectivity and activity for CO production under visible light. A CO evolution rate of 14.93 mu mol h(-1) with 84 % selectivity is achieved, outperforming the bare Ni(OH)(2) (8.51 mu mol h(-1) evolution rate and 45 % selectivity for CO). The structures and physicochemical properties of the Ni(OH)(2)/NC were carefully analyzed by various characterization techniques and density functional theory (DFT) calculations. Results suggest that the NC modification can modulate the electronic structures of Ni(OH)(2), and thus consolidate the adsorption and activation of CO2. Furthermore, the interface charge transfer between photosensitizer and Ni(OH)(2) can also be promoted after NC modification. As a result, the Ni(OH)(2)/NC catalyst exhibits superior activity for CO2-to-CO photoreduction. Moreover, NC-encapsulated NiO (NiO/NC) was successfully prepared under the same conditions. This NiO/NC catalyst also exhibits enhanced selectivity and activity for CO2 reduction with visible light, suggesting the effectiveness of carbon-modification for managing CO2 reduction. This work provides a new avenue to modulate the selectivity and activity of CO2 reduction over transition metal hydroxides or oxide catalysts.

Automated summary

Photoreduction of CO2 to produce carbon-neutral fuels is a sustainable method, but developing robust catalysts for selective CO2 reduction is still challenging. This study presents a hybrid photocatalyst (Ni(OH)(2)/NC) formed by encapsulating nitrogen-doped carbon and Ni(OH)(2), which demonstrates enhanced selectivity and activity for CO production under visible light. The modification of NC can modulate the electronic structures of Ni(OH)(2) and promote the adsorption and activation of CO2, leading to superior CO2-to-CO photoreduction activity. This work provides a new avenue for modulating the selectivity and activity of CO2 reduction over transition metal hydroxides or oxide catalysts.