A silver ion slow-release strategy enables high-concentration boron doping in silver nanocrystals

Light-element doping can effectively regulate the local structure and electronic states of noble metal (such as Pd, Ru, and Ir) based nanomaterials. However, achieving stable high-concentration B incorporation in Ag nanomaterials remains highly challenging. Herein, an ion slow-release strategy based on a solid Ag^I-phenanthroline complex (Ag^I-PT) precursor was used to synthesize high-concentration B-doped Ag nanocrystals (AgB NCs) under ambient conditions. By integrating the Ag^I slow-release process regulated by the coordination-decoordination equilibrium of the Ag^I-PT complex with the continuous reduction of Ag^I by NaBH₄, a nonequilibrium microenvironment featuring low Ag^I flux and a high local B/Ag ratio is established, promoting kinetic trapping of B during Ag lattice formation. The resulting AgB NCs contain 17.2% B without obvious secondary phases. Atomic-scale analyses reveal that high-concentration B doping induces local strain and atomic rearrangement, accompanied by electronic redistribution and a decrease in work function from 4.57 eV for Ag nanocrystals (Ag NCs) to 4.17 eV for AgB NCs. For the electrocatalytic nitrate reduction reaction, AgB NCs exhibit superior activity and kinetics compared with Ag NCs. This work not only provides a mild and effective strategy for achieving high-concentration B doping in Ag nanomaterials but also reveals the positive effect of B doping on the electrocatalytic activity of Ag nanomaterials.