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The viability of the electrolysis of water currently relies on expensive catalysts such as Pt that are far too impractical for industrial-scale use. Thus, there is considerable interest in developing low-cost, earth-abundant nanomaterials and their alloys as a potential alternative to existing standard catalysts. To address this issue, a synergistic approach involving theory and experiment was carried out. The former, based on density functional theory, was conducted to guide the experiment in selecting the ideal dopant and optimal concentration by focusing on 3d, 4d, and 5d elements as dopants on Ni (001) surface. Subsequently, a series of Ni_1−xCr_x(x= 0.01–0.09) alloy nanocrystals (NCs) with size ranging from 8.3 ± 1.6–18.2 ± 3.2 nm were colloidally synthesized to experimentally investigate the hydrogen evolution reaction (HER) activity. A compositional dependent trend for electrocatalytic activity was observed from both approaches with Ni_0.92Cr_0.08NCs showed the lowest ΔG_Hvalue and the lowest overpotential (η₋₁₀) at −10 mA cm⁻²current density (j), suggesting the highest HER activity among all compositions studied. Among alloy NCs, the highest performing Ni_0.92Cr_0.08composition displayed a mixed Volmer–Heyrovsky HER mechanism, the lowest Tafel slope, and improved stability in alkaline solutions. This study provides critical insights into enhancing the performance of earth-abundant metals through doping-induced electronic structure variation, paving the way for the design of high-efficiency catalysts for water electrolysis. 

Group IV alloy nanocrystals (NCs) are a class of direct energy gap semiconductors that show high elemental abundance, low to non-toxicity, and composition-tunable absorption and emission properties. These properties have distinguished Ge1-xSnx NCs as an intriguing material for near-infrared (IR) optical studies. Achieving a material with efficient visible emission requires a modified class of Group IV alloys and the computational studies suggest that this can be achieved with Ge1-x-ySiySnx NCs. Herein, we report a colloidal strategy for the synthesis of bulk-like (10.3 ± 2.5 – 25.5 ± 5.3 nm) and quantum-confined (3.2 ± 0.6 – 4.2 ± 1.1 nm) Ge1-x-ySiySnx alloys that show strong size confinement effects and composition-tunable visible to near IR absorption and emission properties. This synthesis produces a homogeneous alloy with diamond cubic Ge structure and tunable Si (0.9 – 16.1%) and Sn (1.8 – 14.9%) compositions, exceeding the equilibrium solubility of Sn (<1%) in crystalline Si and Ge. Raman spectra of Ge1-x-ySiySnx alloys show a prominent redshift of the Ge-Ge peak and the emergence of a Ge-Si peak with increasing Si/Sn, suggesting the growth of homogeneous alloys. The smaller Ge1-x-ySiySnx NCs exhibit absorption onsets from 1.21 to 1.94 eV for x = 1.8 – 6.8% and y = 0.9 – 16.1% compositions, which are blueshifted from those reported for Ge1-x-ySiySnx bulk alloy films and Ge1-xSnx alloy NCs, indicating the influence of Si incorporation and strong size confinement effects. Solid-state photoluminescence (PL) spectra reveal core-related PL maxima from 1.77 – 1.97 eV in agreement with absorption onsets, consistent with the energy gaps calculated for ~3–4 nm alloy NCs. With facile low-temperature solution synthesis and direct control over physical properties, this methodology presents a noteworthy advancement in the synthesis of bulk-like and quantum-confined Ge1-x-ySiySnx alloys as versatile materials for future optical and electronic studies.