Swathi Srinivasan, Priyanga Marimuthu, Rathinam Yuvakkumar, Ganesan Ravi, Al-Sehemi Abdullah G, Velauthapillai Dhayalan
Department of Physics, Alagappa University, Karaikudi, Tamil Nadu630 003, India.
Adjunct Professor, Department of Physics, Chandigarh University, Mohali, Punjab140 413, India.
ACS Omega. 2023 Jan 17;8(4):3745-3754. doi: 10.1021/acsomega.2c05156. eCollection 2023 Jan 31.
In this work, pristine, 0.02, 0.04, and 0.06 M neodymium (Nd)-doped barium tungstate nanostructures were synthesized via a simple co-precipitation method for the water oxidation process. The obtained X-ray diffraction high-intensity peak at a 2θ value of 26.4° corresponding to the (112) lattice plane confirmed the formation of a tetragonal structure of BaWO. Moreover, the BaWO morphology was examined by scanning electron microscopy, which showed the existence of nanospindles. An energy-dispersive X-ray spectrum confirmed the subsistence of the produced materials, for example, barium (Ba), tungsten (W), oxide (O), and neodymium (Nd), with weight percentages of 28.58, 46.63, 16.64, and 8.16%, respectively. The 0.04 M Nd-doped BaWO product was explored to attain a high surface area of 18.18 m/g, a pore volume of 0.079 cm/g, and a pore diameter of 2.215 nm. Compared to the other prepared electrodes, the 0.04 M Nd-doped BaWO product exhibited low overpotential values of 330 mV and 450 mV to deliver current densities of 10 mA/cm and 50 mA/cm, respectively. In addition, the optimized electrode achieved a small Tafel slope value of 158 mV dec and followed the Volmer-Heyrovsky mechanism. Moreover, the electrical conductivity of BaWO was tuned due to the addition of a rare-earth metal dopant, and it exhibited the charge-transfer resistance and solution resistance values of 0.98 and 1.01 Ω, respectively. The prepared electrocatalyst was further studied by using cyclic voltammetry, and it exhibited a high double-layer capacitance value of 29.3 mF/cm and high electrochemically active surface areas of 1.465 cm. The electrochemical performance was greatly improved depending on the concentration of the doping agent, and it was well consistent with the obtained results. The best electrocatalyst was subjected to a chronoamperometry test, which exhibited excellent stability even after 20 h. Hence, this work suggests that alkaline metal tungstates have a cost-effective, efficient, and promising electrocatalyst, and it is a new approach for the water oxidation process.
在本工作中，通过简单的共沉淀法合成了原始的、0.02 M、0.04 M和0.06 M钕（Nd）掺杂的钨酸钡纳米结构用于水氧化过程。在2θ值为26.4°处获得的对应于（112）晶格平面的X射线衍射高强度峰证实了BaWO四方结构的形成。此外，通过扫描电子显微镜检查了BaWO的形态，其显示存在纳米纺锤体。能量色散X射线光谱证实了所制备材料的存在，例如钡（Ba）、钨（W）、氧（O）和钕（Nd），其重量百分比分别为28.58%、46.63%、16.64%和8.16%。研究了0.04 M Nd掺杂的BaWO产物，其具有18.18 m²/g的高比表面积、0.079 cm³/g的孔体积和2.215 nm的孔径。与其他制备的电极相比，0.04 M Nd掺杂的BaWO产物在分别提供10 mA/cm²和50 mA/cm²的电流密度时表现出330 mV和450 mV的低过电位值。此外，优化后的电极实现了158 mV/dec的小塔菲尔斜率值，并遵循Volmer-Heyrovsky机制。此外，由于添加了稀土金属掺杂剂，BaWO的电导率得到了调节，其电荷转移电阻和溶液电阻值分别为0.98和1.01 Ω。通过循环伏安法对制备的电催化剂进行了进一步研究，其表现出29.3 mF/cm²的高双层电容值和1.465 cm²的高电化学活性表面积。电化学性能根据掺杂剂的浓度有很大提高，并且与所得结果非常一致。对最佳电催化剂进行了计时电流法测试，即使在20小时后仍表现出优异的稳定性。因此，这项工作表明碱金属钨酸盐具有成本效益高、效率高且有前景的电催化剂，并且是水氧化过程的一种新方法。
