Construction of Heterostructured Sn/TiO2 /Si Photocathode for Efficient Photoelectrochemical CO2 Reduction.

Using renewable energy to convert CO2 into liquid products, as a sustainable way to produce fuels and chemicals, has attracted intense attention. Herein, a novel heterostructured photocathode composed of Si wafer, TiO2 layer, and Sn metal particles has been successfully fabricated by combining of a facile hydrothermal and electrodeposition method. The obtained Sn/TiO2 /Si photocathode shows enhanced light absorption performance by the surface plasmon resonance effect of Sn metal. Especially, the Sn/TiO2 /Si photocathode together with rich oxygen vacancy defects jointly promote photoelectrochemical CO2 reduction, harvesting a high faradaic efficiency of HCOOH and a desirable average current density (-4.72 mA cm-2 ) at -1.0 V vs. reversible hydrogen electrode. Significantly, the photocathode Sn/TiO2 /Si also shows good stability due to the design of protecting layer TiO2 . This study provides a facile strategy of constructing an efficient photocathode to improve the light absorption performance and the electron transfer efficiency, exhibiting great potential in the CO2 reduction.

Hierarchically Porous SnO2 Coupled Organic Carbon for CO2 Electroreduction.

Converting CO2 into value-added chemicals or fuels by electrochemical CO2 reduction reaction (CO2 RR) has aroused great interest, whereas designing highly active and selective electrocatalysts is still a challenge. Herein, a novel kind of electrochemical catalyst composed with SnO2 and organic carbon (OC), named as SnO2 /OC, was facilely constructed for CO2 RR. The obtained SnO2 /OC exhibits both high faradaic efficiency for formate (∼75 %) and carbon products (∼95 %) as well as excellent stability. High surface area with hierarchically porous structure and the homogeneous formation of Sn-O-C linkages in SnO2 /OC jointly promote the adsorption and activation of CO2 , as well as fast transport of reactants and products.

Engineering Active Fe Sites on Nickel-Iron Layered Double Hydroxide through Component Segregation for Oxygen Evolution Reaction.

Nickel-iron layered double hydroxide (NiFe LDH) is a promising oxygen evolution reaction (OER) electrocatalyst under alkaline conditions. Much research has been performed to understand the structure-activity relationship of NiFe LDH under OER conditions. However, the specific role of the Fe species remains unclear and under debate. Herein, based on DFT calculations, it was discovered that the edge Fe sites show higher activity towards OER than either the edge Ni sites or lattice sites. Therefore, a facile acid-etching method was proposed to controllably induce the formation of edge Fe sites in NiFe LDH, and the obtained sample exhibited higher OER activity. X-ray absorption near edge structure and extended X-ray absorption fine structure analyses further revealed that the interaction of the edge Fe species with Ni is believed to contribute to the enhancement of the OER performance. This work provides a new understanding of the structure-activity relationship in NiFe LDH and offers a facile method for the design of efficient electrocatalysts in an alkaline environment.