Isolation of Cu Atoms in Pd Lattice: Forming Highly Selective Sites for Photocatalytic Conversion of CO₂ to CH₄

Abstract

Photocatalytic conversion of CO to CH, a carbon-neutral fuel, represents an appealing approach to remedy the current energy and environmental crisis; however, it suffers from the large production of CO and H by side reactions. The design of catalytic sites for CO adsorption and activation holds the key to address this grand challenge. In this Article, we develop highly selective sites for photocatalytic conversion of CO to CH by isolating Cu atoms in Pd lattice. According to our synchrotron-radiation characterizations and theoretical simulations, the isolation of Cu atoms in Pd lattice can play dual roles in the enhancement of CO-to-CH conversion: (1) providing the paired Cu-Pd sites for the enhanced CO adsorption and the suppressed H evolution; and (2) elevating the d-band center of Cu sites for the improved CO activation. As a result, the PdCu-TiO photocatalyst achieves the high selectivity of 96% for CH production with a rate of 19.6 μmol g h. This work provides fresh insights into the catalytic site design for selective photocatalytic CO conversion, and highlights the importance of catalyst lattice engineering at atomic precision to catalytic performance.

Photocatalysis for Hydrogen Production and CO2 Reduction: The Case of Copper‐Catalysts

“…Pt/Cu alloy NPs on TiO 2 mesoporous hollow sphere have been applied in CO 2 reduction for the preferential syngas production . CH 4 was also selectively produced over Pd/Cu bimetallic NPs on TiO 2 . Once again, the content of the two metals in the NPs controlled activity and selectivity.…”

“…The molar ratio of the two metals controlled the energy level of the Cu d ‐band center estimated by theoretical DFT calculations. When Cu atoms are surrounded by more Pd atoms, the electronic structure is affected mostly by the Pd atoms and the d ‐band center of each Cu site is elevated increasing the catalytic activity …”

Recent progress on advanced design for photoelectrochemical reduction of CO2 to fuels

“…Notably, Cu can yield rich hydrocarbon products from CO 2 reduction, such as methanol and methane, which have received giant attention for both photocatalytic and electrocatalytic processes [120][121][122]. In terms of PEC CO 2 reduction, one should also consider those matters to improve the Faradaic efficiency and suppress the competitive reactions when employing metals as co-catalysts.…”

“…Here we name two candidates for this requirement which may boost the development in the future. One is Cu-based catalysts [114,121,122]. Many studies have revealed that Cu-based catalysts can yield deep-reduced products with high selectivity.…”

Engineering Electronic Structure of Stannous Sulfide by Amino‐Functionalized Carbon: Toward Efficient Electrocatalytic Reduction of CO2 to Formate

“…For instance, Zeng et al modified ultrathin SnS 2 nanosheets by nickel doping, achieving a high formate FE of 80% with a current density of 19.6 mA cm −2 at −0.9 V versus reversible hydrogen electrode (RHE), and the improved activity is attributed to the defect level and reduced work function generated by nickel doping . For another example, doping Cu atoms into the Pd lattice can raise the d‐band of center of Cu atoms, thus promoting CO 2 activation and conversion to methane …”