# Atomic-Shell Engineering of GeSx-Au Nanorods Synergistically Suppresses Phonon Scattering and Activates N2 for Near-Infrared-Driven Ammonia Synthesis

## TL;DR

This paper introduces a new nanorod structure that improves ammonia production using near-infrared light by reducing energy loss and activating nitrogen molecules.

## Contribution

The study presents a novel atomic-shell design that synergistically suppresses phonon scattering and activates N2 for efficient photocatalytic ammonia synthesis.

## Key findings

- The GeSx-Au nanorods achieved an NH3 production rate of 1,225.6 μmol g−1 h−1 under NIR irradiation.
- The catalyst showed an apparent quantum efficiency of 1.23% at 880 nm, comparable to UV/visible-driven systems.
- The GeSx shell suppresses phonon scattering and creates active sites for N2 adsorption and activation.

## Abstract

The efficient utilization of near-infrared (NIR) light remains a paramount challenge for solar-driven photocatalytic nitrogen fixation, primarily due to rapid energy dissipation of hot carriers via phonon scattering. Here, we construct a well-defined core–shell heterostructure through the in situ anchoring of an ultrathin, sulfur-vacancy-rich GeSx shell onto gold nanorods (AuNRs)—an atomic-scale configuration that fundamentally suppresses phonon-mediated energy loss. This suppression, directly evidenced by transient absorption spectroscopy through reduced phonon frequency and scattering rate, prolongs the lifetime of plasmon-derived hot electrons. Combined with the vacancy-enabled activation of the robust N≡N bond at exposed Ge sites, this catalyst achieves an exceptional NH3 production rate of 1,225.6 μmol g−1 h−1 under NIR irradiation and a remarkable apparent quantum efficiency of 1.23% at 880 nm—a performance that rivals many ultraviolet/visible-driven systems. Through in situ spectroscopy, transient absorption studies, and theoretical analysis, we elucidate the atomic-level origin of synergistic catalysis: the GeSx shell not only suppresses phonon scattering by reducing phonon frequency and velocity, but also creates electron-deficient Ge sites that function as preferential centers for N2 adsorption and activation, thereby bridging hot-carrier dynamics with molecular reduction kinetics. This work provides a definitive strategy for overcoming fundamental energy loss limitations in plasmonic photocatalysis by concurrently engineering the energy dissipation pathway and the atomic catalytic environment.