ABSTRACT
The extensive utilization of fossil fuels has led to a rapid increase in atmospheric CO2 concentration, resulting in various environmental issues. To reduce reliance on fossil fuels and mitigate CO2 emissions, it is important to explore alternative methods of utilizing CO2 and H2 as raw materials to obtain high-value-added chemicals or fuels. One such method is CO2 methanation, which converts CO2 and H2 into methane (CH4), a valuable fuel and raw material for other chemicals. However, CO2 methanation faces challenges in terms of kinetics and thermodynamics. The reaction rate, CO2 conversion, and CH4 yield need to be improved to make the process more efficient. To overcome these challenges, the development of suitable catalysts is essential. Non-noble metal catalysts have gained significant attention due to their high catalytic activity and relatively low cost. In this paper, the thermodynamics and kinetics of the CO2 methanation reaction are discussed. The focus is primarily on reviewing Ni-based, Co-based, and other commonly used catalysts such as Fe-based. The effects of catalyst supports, preparation methods, and promoters on the catalytic performance of the methanation reaction are highlighted. Additionally, the paper summarizes the impact of reaction conditions such as temperature, pressure, space velocity, and H2/CO2 ratio on the catalyst performance. The mechanism of CO2 methanation is also summarized to provide a comprehensive understanding of the process. The objective of this paper is to deepen the understanding of non-noble metal catalysts in CO2 methanation reactions and provide insights for improving catalyst performance. By addressing the limitations of CO2 methanation and exploring the factors influencing catalyst effectiveness, researchers can develop more efficient and cost-effective catalysts for this reaction.
ABSTRACT
Exploiting organic/inorganic hybrid perovskite solar cells (PSCs) with reduced Pb content is very important for developing environment-friendly photovoltaics. Utilizing of Pb-Sn alloying perovskite is considered as an efficient route to reduce the risk of ecosystem pollution. However, the trade-off between device performance and Sn substitution ratio due to the instability of Sn2+ is a current dilemma. Here, for the first time, the highly efficient Pb-Sn-Cu ternary PSCs are reported by partial replacing of PbI2 with SnI2 and CuBr2 . Sn2+ substitution results in a redshift of the absorption onset, whereas worsens the film quality. Interestingly, Cu2+ introduction can passivate the trap sites at the crystal boundaries of Pb-Sn perovskites effectively. Consequently, a power conversion efficiency as high as 21.08% in inverted planar Pb-Sn-Cu ternary PSCs is approached. The finding opens a new route toward the fabrication of high efficiency Pb-Sn alloying perovskite solar cells by Cu2+ passivation.
ABSTRACT
Effective and stable hole-transporting materials (HTMs) are necessary for obtaining excellent planar perovskite solar cells (PSCs). Herein, we reported a solution-processed composite HTM consisting of a polymer poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) and a small-molecule copper phthalocyanine-3,4',4â³,4â´-tetrasulfonated acid tetrasodium salt (TS-CuPc) with optimized doping ratios. The composite HTM is crucial for not only enhancing the hole transport and extraction but also improving the perovskite crystallization. In addition, the composite HTM can weaken the indium tin oxide erosion by reducing the acidity and increasing the dispersibility of the PEDOT:PSS aqueous dispersion via incorporating suitable TS-CuPc. Consequently, a highly efficient device was fabricated with a power conversion efficiency (PCE) of 17.29%. Its short-circuit current (JSC) is 22.23 mA/cm2, and its open-circuit voltage (VOC) is 1.01 V. Meanwhile, it exhibited a higher fill factor (FF) of 77% and improved cell stability. The developed composite HTM provides a good potential anode interfacial layer for fabricating outstanding PSCs.
