The continuously increasing CO2 released from human activities poses a great threat to human survival by fluctuating global climate and disturbing carbon balance among the four reservoirs of the biosphere, earth, air, and water. Converting CO2 to value-added feedstocks via electrocatalysis of the CO2 reduction reaction (CO2RR) has been regarded as one of the most attractive routes to re-balance the carbon cycle, thanks to its multiple advantages of mild operating conditions, easy handling, tunable products and the potential of synergy with the rapidly increasing renewable energy (i.e., solar, wind). Instead of focusing on a special topic of electrocatalysts for the CO2RR that have been extensively reviewed elsewhere, we herein present a rather comprehensive review of the recent research progress, in the view of associated value-added products upon selective electrocatalytic CO2 conversion. We initially provide an overview of the history and the fundamental science regarding the electrocatalytic CO2RR, with a special introduction to the design, preparation, and performance evaluation of electrocatalysts, the factors influencing the CO2RR, and the associated theoretical calculations. Emphasis will then be given to the emerging trends of selective electrocatalytic conversion of CO2 into a variety of value-added products. The structure-performance relationship and mechanism will also be discussed and investigated. The outlooks for CO2 electrocatalysis, including the challenges and opportunities in the development of new electrocatalysts, electrolyzers, the recently rising operando fundamental studies, and the feasibility of industrial applications are finally summarized.

Electrocatalysis for CO2 conversion: from fundamentals to value-added products

The electrochemical carbon dioxide reduction reaction (CO2 RR) provides an attractive approach to convert renewable electricity into fuels and feedstocks in the form of chemical bonds. Among the different CO2 RR pathways, the conversion of CO2 into CO is considered one of the most promising candidate reactions because of its high technological and economic feasibility. Integrating catalyst and electrolyte design with an understanding of the catalytic mechanism will yield scientific insights and promote this technology towards industrial implementation. Herein, we give an overview of recent advances and challenges for the selective conversion of CO2 into CO. Multidimensional catalyst and electrolyte engineering for the CO2 RR are also summarized. Furthermore, recent studies on the large-scale production of CO are highlighted to facilitate industrialization of the electrochemical reduction of CO2 . To conclude, the remaining technological challenges and future directions for the industrial application of the CO2 RR to generate CO are highlighted.

Advances and Challenges for the Electrochemical Reduction of CO2 to CO: From Fundamentals to Industrialization

Global development has been heavily reliant on the overexploitation of natural resources since the Industrial Revolution. With the extensive use of fossil fuels, deforestation, and other forms of land-use change, anthropogenic activities have contributed to the ever-increasing concentrations of greenhouse gases (GHGs) in the atmosphere, causing global climate change. In response to the worsening global climate change, achieving carbon neutrality by 2050 is the most pressing task on the planet. To this end, it is of utmost importance and a significant challenge to reform the current production systems to reduce GHG emissions and promote the capture of CO2 from the atmosphere. Herein, we review innovative technologies that offer solutions achieving carbon (C) neutrality and sustainable development, including those for renewable energy production, food system transformation, waste valorization, C sink conservation, and C-negative manufacturing. The wealth of knowledge disseminated in this review could inspire the global community and drive the further development of innovative technologies to mitigate climate change and sustainably support human activities.

Technologies and perspectives for achieving carbon neutrality

Biologically-mediated carbon capture and utilization by microalgae towards sustainable CO2 biofixation and biomass valorization – A review

Conversing CO2 into value‐added chemicals endows electrochemical CO2 reduction reaction (CO2RR) with the potential to tackle over issues induced by the increased CO2 level in the atmosphere. The associated technological viability of this process is highly dependent on exploring efficient electrocatalysts. In this work, we successfully synthesized nitrogen and sulfur co‐doped carbon nanosheets (NS‐CNSs), which are comprehensively characterized by a variety of characterization techniques. When used as the catalyst for CO2RR, the NS‐CNSs exhibit remarkably high catalytic activity and selectivity with a Faradaic efficiency of ∼85.4 % for CO production and long‐term durability. The superior performance of this material majorly originates from the unique nanosheets structure with large porosity and the co‐doped S and N in the nanosheets, which exposed larger electrochemical activity surface areas and more active sites for promoting CO2 reduction.

Nitrogen and Sulfur Co‐doped Carbon Nanosheets for Electrochemical Reduction of CO2

Achieving carbon neutrality: the effect of China pilot Free Trade Zone policy on green technology innovation

Optimal dispatch of heat and power loads for combined heat and power (CHP) power plants is an effective solution to further improve energy efficiency and reduce energy consumption. To obtain a better load dispatch effect, this paper used the Particle Swarm Optimization (PSO) algorithm based on Levy flight (Levy-PSO algorithm) to solve the optimal dispatch problem. Meanwhile, the constraint condition processing method which is based on the characteristics of the internal thermoelectric load and external total load of electricity and heat network of thermoelectric units is also proposed to combine with the Levy-PSO algorithm for solving the problem. The optimal results are obtained via using the PSO and Levy-PSO algorithms for a typical CHP plant of seven units. The results show that the power generation cost obtained from the Levy-PSO algorithm is the lowest (10121.84$), which is close to the results of the literature and is better than the optimization results of the traditional PSO algorithm. Moreover, the results show that the constraint processing method adopted in this paper can well solve the characteristics of multiple constraints of load optimal dispatch problem. Meanwhile, the comparison results between the PSO algorithm and Levy-PSO algorithm indicate that the Levy-PSO algorithm has more obvious advantages in the performance of the algorithm. When combining with the proposed constraint processing scheme, the Levy-PSO algorithm shows better convergence and robustness, which is more suitable for solving similar practical engineering problems of heating and power optimal load distribution.

Chaoyang Tu

Papers

Electrocatalysis for CO2 conversion: from fundamentals to value-added products

Nitrogen and Sulfur Co‐doped Carbon Nanosheets for Electrochemical Reduction of CO2

Achieving carbon neutrality: the effect of China pilot Free Trade Zone policy on green technology innovation

Research on Heating and Power Load Optimal Dispatch Based on the Particle Swarm Optimization Algorithm Combined with the Levy Flight