Hydrogen energy has attracted a lot of attention due to its ultra-high energy density and environmental protection properties, and ruthenium (Ru) is considered a promising catalyst candidate for catalyzing basic hydrogen evolution reaction (HER), but it needs to optimize the adsorption of hydrogen to improve electrocatalytic activity. Nowadays, strain engineering has been proved to be an effective strategy to adjust the binding strength of key reaction intermediates and enhance the catalytic activity, because the compressive strain will widen the D-band and move the center of the D-band downward, thereby weakening the hydrogen adsorption strength of RU, but it is still a challenge to systematically study the influence of strain effect on the hydrogen adsorption of RU.
Recently,Wang Deli of Huazhong University of Science and TechnologyRuthenium-doped nickel-chromium layered double hydroxide nanosheets (Ru-NICR LDH) with different compressive strain levels were constructed to regulate hydrogen adsorption by annealing oxygen vacancies in H2 AR with different volume fractions. The experimental results show that the optimal Ru-NiCR LDH-R catalyst can produce a current density of 100 mA cm-2 with a low overpotential of only 30 mV, and exhibits significant long-term durability, with a slight attenuation of activity after 10,000 CV cycles, and continuous stable operation at 10 mA cm-2 for about 100 hours. Theoretical calculations show that the enhancement of the electrocatalytic performance of the RU-NICR LDH is attributed to the weakening of hydrogen adsorption due to the downward shift of the D-band center induced by the strain effect, which proves the effectiveness of strain engineering in the design of active catalysts for hydrogen production.
At the same time, the researchers studied the D-band structure of the RU-NICR LDH-R sample by ultraviolet photoelectron spectroscopy (UPS). The results show that the valence band of Ru-NiCR LDH-R is the farthest away from the Fermi level, and the center of the D band decreases from the Fermi level, indicating that the adsorption strength of hydrogen intermediates on the surface of the catalyst is weakened, which further adjusts the binding strength of hydrogen and improves the performance of basic HER. In addition, under the conditions of 80 and 90, the anion exchange membrane water electrolyzer (AEMWE) using the RUR-NICR LDH-R as the cathode was used in 1The current densities at 8 V are 1800 and 1940 mA cm2, respectively, showing great potential for industrial applications. In conclusion, this work proves the effectiveness of strain engineering in the design of HER active catalysts, and provides a promising strategy for the rational design of efficient HER electrocatalysts.
strain-engineered ru-nicr ldh nanosheets boosting alkaline hydrogen evolution reaction. acs catalysis, 2024. doi: 10.1021/acscatal.3c05550