Articolo in rivista, 2022, ENG, 10.1021/acsenergylett.2c00941

Hydrogen Spillover and Storage on Graphene with Single-Site Ti Catalysts

Chen, Jhih-Wei; Hsieh, Shang-Hsien; Wong, Sheng-Shong; Chiu, Ya-Chi; Shiu, Hung-Wei; Wang, Chia-Hsin; Yang, Yaw-Wen; Hsu, Yao-Jane; Convertino, Domenica; Coletti, Camilla; Heun, Stefan; Chen, Chia-Hao; Wu, Chung-Lin

Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan; National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan; Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Pisa, 56127, Italy; NEST, Istituto Nanoscienze-CNR, Scuola Normale Superiore, Pisa, 56127, Italy;

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 band gap opening, and X-ray absorption spectra reveal the formation of C-H bonds, both indicating partial graphene hydrogenation. With increasing Ti deposition and H-2 exposure, the Ti atoms tend to aggregate to form nanocluster catalysts and yield 13.5% sp(3)-hybridized carbon atoms corresponding to a hydrogen-storage capacity of 1.11 wt % (excluding the weight of the Ti nanoclusters [Bhowmick, R. et al. J. Am. Chem. Soc.2011, 133 (14), 5580]). Our results demonstrate how a simple spillover process at Ti SACs can lead to covalent hydrogen bonding on graphene, thereby providing a strategy for the rational design of carbon-supported single-site catalysts.

ACS energy letters 7 (7), pp. 2297–2303

Keywords

Atoms; Catalyst supports; Energy gap; Hydrogen bonds; Hydrogen storage; Nanocatalysts; Nanoclusters; Synchrotron radiation; X ray absorption

CNR authors

Heun Stefan

CNR institutes

NANO – Istituto Nanoscienze