Hydrogen spillover and storage for single-site metal catalysts, including single-atom catalysts (SACs) and single nanocluster catalysts, have been elucidated for various supports but remain poorly understood for inert carbon supports. Here, we use synchrotron radiation-based methods to investigate the role of single-site Ti catalysts on graphene for hydrogen spillover and storage. Our in-situ angle-resolved photoemission spectra results demonstrate a bandgap opening and the X-ray absorption spectra reveal the formation of C-H bonds, both indicating the partial graphene hydrogenation. With increasing Ti deposition and H2 exposure, the Ti atoms tend to aggregate to form nanocluster catalysts and yield 13.5% sp3-hybridized carbon atoms corresponding to a hydrogen-storage capacity of 1.11 wt% (excluding the weight of the Ti nanoclusters [1]). Our results demonstrate how a simple spillover process at Ti SACs can lead to covalent hydrogen bonding on graphene, thereby providing a strategy for a rational design of carbon-supported single-site catalysts.
@article{arxiv.2206.06638,
title = {Hydrogen spillover and storage on graphene with single-site Ti catalysts},
author = {Jhih-Wei Chen and Shang-Hsien Hsieh and Sheng-Shong Wong and Ya-Chi Chiu and Hung-Wei Shiu and Chia-Hsin Wang and Yaw-Wen Yang and Yao-Jane Hsu and Domenica Convertino and Camilla Coletti and Stefan Heun and Chia-Hao Chen and Chung-Lin Wu},
journal= {arXiv preprint arXiv:2206.06638},
year = {2022}
}