Search

The activity of Li-intercalated MoS2 phases for the hydrogen evolution reaction is investigated using density functional theory. The most stable semiconducting 2H phase, the metallic 1T′ phase, and a polymorphous surface composed of alternating H and T′ phases (1T″) are investigated. The local structure of the MoS2 surface is found to define its reactivity. In all cases, active sites for the hydrogen evolution process are restricted to T-like sulphur sites. Li-intercalation is found to promote hydrogen evolution reaction reactivity for the H phase whilst having little effect on the T phase. While improved compared to the non-intercalated phase, the Li-intercalated H phase MoS2 still has minimal activity for the hydrogen evolution reaction. The same effect of intercalation is also found for another transition metal dichalcogenide, MoSe2. The ability to improve reactivity in this way makes ion intercalation a promising space for designing new 2D catalysts for the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

The activity of Li-intercalated MoS2 phases for the hydrogen evolution reaction is investigated using density functional theory. The most stable semiconducting 2H phase, the metallic 1T′ phase, and a polymorphous surface composed of alternating H and T′ phases (1T″) are investigated. The local structure of the MoS2 surface is found to define its reactivity. In all cases, active sites for the hydrogen evolution process are restricted to T-like sulphur sites. Li-intercalation is found to promote hydrogen evolution reaction reactivity for the H phase whilst having little effect on the T phase. While improved compared to the non-intercalated phase, the Li-intercalated H phase MoS2 still has minimal activity for the hydrogen evolution reaction. The same effect of intercalation is also found for another transition metal dichalcogenide, MoSe2. The ability to improve reactivity in this way makes ion intercalation a promising space for designing new 2D catalysts for the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

• Developed an advanced microkinetic model based on first-principles, accounting for adsorbate interactions. • Uncovering the full Pd (1 1 1) mechanism of formic acid dehydrogenation and highlighting the importance of coverage. • Our kinetic analysis aligns with experimental values at 373 K, considering H coverage. • Simulation results align with experiments, approaching 100 % H 2 selectivity on Pd (1 1 1) for formic acid decomposition. As a key liquid organic hydrogen carrier, investigating the decomposition of formic acid (HCOOH) on the Pd (1 1 1) transition metal surface is imperative for harnessing hydrogen energy. Despite a multitude of studies, the major mechanisms and key intermediates involved in the dehydrogenation process of formic acid remain a great topic of debate due to ambiguous adsorbate interactions. In this research, we develop an advanced microkinetic model based on first-principles calculations, accounting for adsorbate–adsorbate interactions. Our study unveils a comprehensive mechanism for the Pd (1 1 1) surface, highlighting the significance of coverage effects in formic acid dehydrogenation. Our findings unequivocally demonstrate that H coverage on the Pd (1 1 1) surface renders formic acid more susceptible to decompose into H 2 and CO 2 through COOH intermediates. Consistent with experimental results, the selectivity of H 2 in the decomposition of formic acid on the Pd (1 1 1) surface approaches 100 %. Considering the influence of H coverage, our kinetic analysis aligns perfectly with experimental values at a temperature of 373 K. [ABSTRACT FROM AUTHOR]