Electronic structure engineering of single atomic sites by plasmon-induced hot electrons for highly efficient and selective photocatalysis

Single atom (SA) catalysts have achieved great success on highly selective heterogeneous catalysis due to their abundant and homogeneous active sites. The electronic structures of these active sites, restrained by their localized coordination environments, significantly determine their catalytic performances, which are difficult to manipulate. Here, we investigated the effect of localized surface plasmon resonance (LSPR) on engineering the electronic structures of single atomic sites. Typically, core–shell structures consisted of Au core and transition metal SAs loaded N-doped carbon (CN) shell were constructed, namely Au@M-SA/CN (M = Ni, Fe, and Co). It was demonstrated that plasmon-induced hot electrons originated from Au were directionally injected to the M-SAs under visible light irradiation, which significantly changed their electronic structures and meanwhile facilitated improved overall charge separation efficiency. The as-prepared Au@Ni-SA/CN exhibited highly efficient and selective photocatalytic CO₂ reduction to CO performance, which is 20.8, 17.5, and 6.9 times those of Au nanoparticles, Au@CN, and Ni-SA/CN, respectively. Complementary spectroscopy analysis and theoretical calculations confirmed that the plasmon enhanced Ni-SA/CN sites featured increased charge density for efficient intermediate activation, contributing to the superb photocatalytic performance. The work provides a new insight on plasmon and atomic site engineering for efficient and selective catalysis.