Laser-ablation assisted strain engineering of gold nanoparticles for selective electrochemical CO2 reduction

Strain engineering can endow versatile functions, such as refining d-band center and inducing lattice mismatch, on catalysts for a specific reaction. To this end, effective strain engineering for introducing strain on the catalyst is highly sought in various catalytic applications. Herein, a facile laser ablation in liquid (LAL) strategy is adopted to synthesize gold nanoparticles (Au NPs) with rich compressive strain (Au-LAL) for electrochemical CO2 reduction. It is demonstrated that the rich compressive strain can greatly promote the electrochemical CO2 reduction performance of Au, achieving a CO partial current density of 24.9 mA cm(-2) and a maximum CO faradaic efficiency of 97% at -0.9 V for Au-LAL, while it is only 2.77 mA cm(-2) and 16.2% for regular Au nanoparticles (Au-A). As revealed by the in situ Raman characterization and density functional theory calculations, the presence of compressive strain can induce a unique electronic structure change in Au NPs, significantly up-shifting the d-band center of Au. Such a phenomenon can greatly enhance the adsorption strength of Au NPs toward the key intermediate of CO2 reduction (i.e., *COOH). More interestingly, we demonstrate that, an important industrial chemical feedstock, syngas, can be obtained by simply mixing Au-LAL with Au-A in a suitable ratio. This work provides a promising method for introducing strain in metal NPs and demonstrates the important role of strain in tuning the performance and selectivity of catalysts.

Automated summary

This study demonstrates the synthesis of gold nanoparticles with rich compressive strain and the significant improvement in electrochemical CO2 reduction performance. The presence of compressive strain alters the electronic structure of gold nanoparticles, enhancing the adsorption strength towards key intermediates.