Ge optimized electron environments of binary alloy active phase loaded on nGeNi/TA catalyst to match n-ethylcarbazole orbitals to boost hydrogen storage processes

Developing high-performance non-precious metal catalysts for liquid organic hydrogen storage is crucial for advancing hydrogen energy technologies. Herein, we proposed a strategy in which doped Ge promoters optimized electron environments of nGeNi active phase loaded on titanium-aluminum composite oxide support with highly ordered 2D hexagonal mesopores (nGeNi/TA, n = 0, 0.5, 1, and 2 wt%), successfully establishing electron-rich active phase with high matching to HOMO orbital of N-Ethylcarbazole (NEC) molecule. Meanwhile, both d-band center of active phase and electron densities of its conduction band were effectively adjusted. These improvements not only retained ability of nGeNi active phase to activate NEC and its intermediates, but also suitably weakened strong π-d interaction with their aromatic rings. Consequently, adsorption energy of each intermediate species was almost close to average energy of hydrogenation conversion stages, thereby decreasing desorption energy of complete hydrogenation product (12H). Compared with 0GeNi/TA catalyst, NEC conversion rate on the best 1GeNi/TA catalyst at low temperature (220℃) greatly increased by approximately 118 %, and 12H selectivity and its yield sharply improved by approximately 112 % and 132 %, respectively. Moreover, excessive accumulations of intermediate species were also effectively mitigated.