Sub-nanometer-precision of noble metal catalysts with atomic contact to support simultaneously played a pivotal role in determining their catalytic activities. However, achieving predictable construction of noble metal cocatalysts at sub-nanometer scales remained a significant challenge. Herein, we demonstrated an in situ lattice atom abstraction strategy for sub-nanometer-precision construction of size-controlled Ag cocatalysts. Host lattice Ag⁺ was abstracted by tri-n-octylphosphine (TOP) due to its strong complexing ability towards Ag⁺, and was in situ reduced into metal Ag cocatalysts on the surface of AgInS₂ nanorods (AIS NRs), which was accelerated by the synergistic effect of TOP and oleylamine (OAm). This in situ lattice atom abstraction strategy avoided the undesired cation exchange reaction and simplified complex reaction processes, facilitating Ag cocatalysts with controlled sizes ranging from 0.60 to 6.76 nm with an unprecedented sub-nanometer precision. This set of Ag cocatalysts with sub-nanometer precision provided an ideal platform for systematically investigating cocatalyst size effects. Nano-sized Ag cocatalysts possessed superior separation and transfer ability over cluster-sized Ag cocatalysts, leading to the enhancement of photocurrent density 2.78 times higher than cluster-sized Ag cocatalysts. While cluster-sized Ag cocatalysts possessed higher surface catalytic activity, contributing to the improvement of Faradaic efficiency up to 97.5% from 74.4%.

Here we report a synthetic strategy for controllable construction of yolk-shell and core-shell plasmonic metal@semiconductor hybrid nanocrystals through modulating the kinetics of sulfurization reaction followed by cation exchange. The yielded yolk-shell structured products feature exceptional crystallinity and more importantly, the intimately adjoined and sharp interface between plasmonic metal and semiconductor which facilitates efficient charge carrier communications between them. By exploiting the system composed of Au nanorods and p-type PbS as a demonstration, we show that the Au@PbS yolk-shell nanorods manifest notable improvement in visible and near infrared light absorption compared to the Au@PbS core-shell nanorods as well as hollow PbS nanorods. Moreover, the photocathode constituted by Au@PbS yolk-shell nanorods affords the highest photoelectrochemical activities both under simulated sunlight and λ > 700 nm light irradiation. The superior performance of Au@PbS yolk-shell nanorods is considered arising from the combination of the favorable structural advantages of yolk-shell configuration and the surface plasmon resonance enhancement effect. We envision that the reported synthetic strategy can offer a valuable means to create hybrid nanocrystals with desirable structures and functions that enable to harness the photogenerated charge carriers, including the plasmonic hot holes, in wide-range solar-to-fuel conversion.