钙掺杂Y₂Ru₂O₇烧绿石氧化物的制备及其电催化析氢性能研究

Preparation of Calcium-Doped Y₂Ru₂O₇ Pyrochlore Oxide and Its Electrocatalytic Hydrogen Precipitation Properties

摘要: 本研究合成了烧绿石氧化物Y₂Ru₂O₇ (YRO)和Ca掺杂的Y_1.7Ca_0.3Ru₂O₇ (YCRO)材料，系统研究了它们在碱性介质中的电催化析氢性能(HER)，并与商业Pt/C和RuO₂催化剂进行了对比。结果表明，Ca掺杂显著提高了催化活性，使达到10 mA∙cm⁻²电流密度所需过电位从162 mV大幅降低至81 mV，塔菲尔斜率从91.8降至63.8 mV∙dec⁻¹，接近商业Pt/C催化剂(52 mV, 54.0 mV∙dec⁻¹)。YCRO还表现出优异的稳定性，在2000次循环伏安循环和20小时连续电解后活性几乎无衰减。通过多种表征手段(XRD、XPS、SEM和TEM等)，揭示了Ca掺杂增强HER性能的电催化机理机制，Ca²⁺部分替代Y³⁺，导致Ru的d-band中心下移(靠近费米能级)，优化了氢吸附能；提高了氧空位浓度和表面亲水性，改善了水分子吸附和活化。研究为开发高效金属氧化物析氢电催化剂提供了新思路和理论依据。

Abstract: In this thesis, pyrochlore oxide Y₂Ru₂O₇ (YRO) and Ca-doped Y_1.7Ca_0.3Ru₂O₇ (YCRO) materials have been synthesized, and their electrocatalytic hydrogen-removal performance (HER) in alkaline media has been systematically investigated and compared with commercial Pt/C and RuO₂ catalysts. The results showed that Ca doping significantly improved the catalytic activity, resulting in a significant reduction of the overpotential required to reach a current density of 10 mA∙cm⁻² from 162 mV to 81 mV, and a reduction of the Tafel slope from 91.8 to 63.8 mV∙dec⁻¹, which is close to that of commercial Pt/C catalysts (52 mV, 54.0 mV∙dec⁻¹). YCRO also exhibits excellent stability, with virtually no decay in activity after 2000 cyclic voltammetry cycles and 20 hours of continuous electrolysis. The electrocatalytic mechanism of Ca doping to enhance HER performance was revealed by various characterization means (XRD, XPS, SEM and TEM, etc.), where Ca²⁺ partially replaces Y³⁺, leading to a downward shift of the d-band center of Ru (close to the Fermi energy level) and optimizing the hydrogen adsorption energy; and an increase in the concentration of the oxygen vacancies and the hydrophilicity of the surface, which improves the adsorption and activation of water molecules. The study provides new ideas and theoretical basis for the development of efficient metal oxide hydrogen precipitation electrocatalysts.