Sohail Umair, Pervaiz Erum, Khosa Rafiq, Ali Maryum
Heterogeneous Catalysis Lab, Department of Chemical Engineering, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST) Islamabad 44000 Pakistan
Nanoscale Adv. 2024 Aug 19;6(20):5092-105. doi: 10.1039/d4na00289j.
Conventional energy resources are diminishing, and environmental pollution is constantly increasing because of the excessive use of fossil fuels to sustain the ever-increasing population and industrialization. This has raised concerns regarding a sustainable future. In the pursuit of addressing sustainability in industrial processes and energy systems, the production of green hydrogen is considered a promising and crucial solution to meet the growing energy demands. Water-splitting is one of the most effective technologies for producing clean and carbon-neutral hydrogen. Water-splitting is a scientifically emerging application, but it is commercially limited due to its economic non-viability. The sluggish kinetics and the high overpotential needed for the water-splitting reactions (HER and OER) have encouraged the scientific community to design electrocatalysts that address the concerns of low activity, efficiency and stability. Designing a hybrid catalyst using metal-organic frameworks (MOFs) with transition metal carbides can be a suitable approach to address the deficiencies of conventional water-splitting catalysts. In this study, we have designed and fabricated an electrocatalyst of tungsten carbide (WC) with two different MOFs (Zr-based and Fe-based) and explored their electrocatalytic activity for hydrogen generation in an alkaline medium. It should be noted that hybrids of tungsten carbide with a zirconia MOF (UiO-66) showed better electrocatalytic activity with low overpotentials of 104 mV (HER) and 152 mV (OER) at a current density of 10 mA cm. This superior activity of WC with the Zr-MOF in comparison to the Fe-MOF is due to the synergistic effect of Zr present in UiO-66 grown on the WC matrix. Moreover, UiO-66 provides a larger electrocatalytic active surface area, so available active sites are more in UiO-66 as compared to the Fe-MOF. These findings set the stage for the systematic development and production of bi-functional hybrid catalysts with the potential to be utilized in water-splitting processes.
传统能源正在枯竭，由于过度使用化石燃料来维持不断增长的人口和工业化进程，环境污染也在持续加剧。这引发了人们对可持续未来的担忧。在寻求解决工业生产过程和能源系统可持续性问题的过程中，绿色氢的生产被视为满足不断增长的能源需求的一个有前景且至关重要的解决方案。水分解是生产清洁且碳中和氢的最有效技术之一。水分解是一项新兴的科学应用，但由于其经济上不可行，在商业上受到限制。水分解反应（析氢反应和析氧反应）的缓慢动力学和所需的高过电位促使科学界设计能够解决低活性、低效率和稳定性问题的电催化剂。使用金属有机框架（MOF）与过渡金属碳化物设计混合催化剂可能是解决传统水分解催化剂缺陷的一种合适方法。在本研究中，我们设计并制备了碳化钨（WC）与两种不同MOF（锆基和铁基）的电催化剂，并探索了它们在碱性介质中制氢的电催化活性。需要注意的是，碳化钨与氧化锆MOF（UiO - 66）的混合物在10 mA cm的电流密度下表现出更好的电催化活性，析氢过电位低至104 mV，析氧过电位低至152 mV。与铁基MOF相比，WC与锆基MOF的这种优异活性归因于生长在WC基体上的UiO - 66中锆的协同效应。此外，UiO - 66提供了更大的电催化活性表面积，因此与铁基MOF相比，UiO - 66中的可用活性位点更多。这些发现为系统开发和生产具有用于水分解过程潜力的双功能混合催化剂奠定了基础。
