Electrocatalytic CO2 reduction (ECO2R) has been considered as a promising approach to convert CO2 into valuable chemicals and fuels. CO2 loss in conventional alkaline electrolyzers has been recognized as a major obstacle that compromising the efficiency of the ECO2R system. This review firstly conducts an in-depth assessment of the origin and influence of CO2 loss. On this basis, this work summarizes electrolyzer configurations based on novel material and structure design that are capable of tackling CO2 loss, including acidic electrolyzer, bipolar membrane (BPM) derived electrolyzer, cascade electrolyzer, liquid-phase-anode electrolyzer, and liquid-fed electrolyzer. The design strategies and challenges of these carbon efficient electrolyzers have been deliberated in detail. By comparing and analyzing the advantages and limitations of various electrolyzer designs, this work aims to provide some guidelines for the development of efficient ECO2R technology toward large-scale industrial application.

Given the increasing threat of economic downturns and global warming, the governments of developing countries urgently need effective measures that can both stimulate economic development and promote low-carbon transitions. As a widely accepted method for stimulating economic growth, the improvement of the business environment and its effect on economic activity have been fully discussed. However, little is known about whether and how the business environment affects the low-carbon transition. By leveraging city-level data from China, this paper exploits whether and through which channels a favorable business environment promotes a low-carbon transition. We find that improving the business environment has a positive impact on carbon efficiency. This relationship is verified to be robust through various alternative tests. Additionally, it is demonstrated that enhancing the business environment can increase carbon efficiency by promoting green technology progress and stimulating new firm entry. Heterogeneity analysis indicates that the positive effect of the business environment is pronounced for cities with intensive environmental regulation, sufficient environmentally targeted fiscal expenditure, and loose economic growth requirements. This paper reveals the unintentional environmental gains of business environment optimization and provides important insights into the low-carbon transition for developing economies.

Carbon dioxide (CO2) emissions and haze pollution are often thought to have the same origin, the burning of fossil fuels. However, their relationship is not always synergistic and may even exhibit mutual constraints. Carbon-biased technological progress has emerged as a promising approach for simultaneously achieving three goals - to reduce CO2 emissions, alleviate the haze pressure, and keep economic growth. This study empirically investigates the impact and mechanisms of carbon-biased technological progress on carbon haze collaborative governance using data from 286 Chinese cities during 2006-2021. The results indicate that: (1) Carbon biased technological progress positively influences carbon haze collaborative governance. (2) This progress achieves coordination by enhancing element allocation efficiency, carbon efficiency, and responding to public environmental demands. (3) The facilitating role of carbon biased technological progress to carbon haze collaborative governance will work better if external conditions are met. Moreover, the effectiveness of carbon-biased technological progress in promoting coordination is contingent upon high levels of marketization, government intervention, environmental regulation, and technical advancements. Local and regional governments should foster conducive conditions for carbon dioxide and haze pollution coordination, optimize the allocation and flow of carbon resources, ensure harmonization between environmental regulation policies and other sectors, and bolster international cooperation and technical knowledge exchange to collectively address global environmental challenges.

The middle and lower reaches of the Yangtze River is one of main grain production areas in China, which is of great significance to food security. Understanding the carbon footprint of major grain crop production is helpful to develop high-yield and low-carbon agriculture. Based on the data of yield, sown area and farmland production input of main grain crops (rice, wheat and maize) in six provinces (Jiangsu, Anhui, Jiangxi, Hubei, Hunan, and Zhejiang) in the middle and lower reaches of the Yangtze River from 2011 to 2020, we estimated carbon footprint in the production of the three grain crops. The results showed that from 2011 to 2020, yield per unit area, planting area, and total yield of rice, wheat and maize were the highest in Jiangsu Province. In terms of area-scaled carbon footprint, rice in the middle and lower reaches of the Yangtze River had the highest area-scaled carbon footprint, with an average of 2.0 t CE·hm-2, followed by wheat and maize. The area-scaled carbon footprint of the three staple crops was increasing. In terms of yield-scaled carbon footprint, rice was the highest, with an average of 0.8 kg CE·kg-1, followed by wheat and maize. In terms of carbon input structure, irrigation electricity, chemical fertilizers and pesticides accounted for a relatively high proportion. Irrigation electricity accounted for 35.0%, 36.3%, and 33.2% of the total carbon input of rice, wheat and maize, respectively. Chemical fertilizers accounted for 28.8%, 32.5%, and 32.5%, respectively, while pesticides accounted for 24.2%, 13.3% and 11.5%, respectively. In terms of carbon efficiency, maize had the highest (3.9 kg·kg-1 CE), followed by rice and wheat. With the green development of agriculture, carbon emission in the production of major grain crops in the middle and lower reaches of the Yangtze River could be reduced by improving irrigation efficiency, fertilizer utilization efficiency, pesticide utilization efficiency and mechanized operation efficiency, as well as diversification of straw returning, cultivation of new varieties and policy leverage.
长江中下游是我国粮食生产区之一,对粮食安全保障有重要意义。解析主要粮食作物生产的碳足迹,有助于发展丰产低碳农业。本研究基于2011—2020年长江中下游地区6个省份(江苏省、安徽省、江西省、湖北省、湖南省和浙江省)主要粮食作物(水稻、小麦和玉米)的产量、播种面积、农田生产投入等数据,对该区域上述3种主粮作物的生产碳足迹进行估算。结果表明: 2011—2020年间,江苏省的水稻、小麦和玉米不论在单产、种植面积或总产上均居首位。在单位面积碳足迹上,长江中下游地区的水稻最高,平均达到2.0 t CE·hm-2,小麦次之,玉米最低,且3种主粮作物的单位面积碳足迹不断升高。在单位籽粒产量碳足迹上,水稻最高,平均达到0.8 kg CE·kg-1,小麦次之,玉米最低。在碳投入结构上,灌溉用电、化肥和农药的投入占比较高,灌溉用电分别占水稻、小麦和玉米总碳投入的35.0%、36.3%和33.2%,化肥分别占28.8%、32.5%和32.5%,农药分别占24.2%、13.3%和11.5%。在碳效率上,玉米最高,为3.9 kg·kg-1 CE,水稻次之,小麦最低。随着农业绿色发展的推进,通过提高灌溉效率、化肥利用效率、农药利用率和机械化作业效率,以及秸秆还田多样化、新品种培育和政策杠杆等多种途径,能够合力降低长江中下游地区主要粮食作物生产过程中的碳排放。.

Carbon dioxide reduction reaction (CO2 RR) provides an efficient pathway to convert CO2 into desirable products, yet its commercialization is greatly hindered by the huge energy cost due to CO2 loss and regeneration. Performing CO2 RR under acidic conditions containing alkali cations can potentially address the issue, but still causes (bi)carbonate deposition at high current densities, compromising product Faradaic efficiencies (FEs) in present-day acid-fed membrane electrode assemblies. Herein, we present a strategy using a positively charged polyelectrolyte-poly(diallyldimethylammonium) immobilized on graphene oxide via electrostatic interactions to displace alkali cations. This enables a FE of 85 %, a carbon efficiency of 93 %, and an energy efficiency (EE) of 35 % for CO at 100 mA cm-2 on modified Ag catalysts in acid. In a pure-water-fed reactor, we obtained a 78 % CO FE with a 30 % EE at 100 mA cm-2 at 40 °C. All the performance metrics are comparable to or even exceed those attained in the presence of alkali metal cations.

Achieving global climate change mitigation targets requires low-carbon production in agriculture. In such an endeavor, a new classification of climate-adaptive technology is defined to affect agriculture towards the low-carbon direction, but such an impact has seldom been empirically tested in the literature. In this paper, we investigate the impact of climate-adaptive technological innovation on agricultural carbon efficiency, a proxy for low-carbon agriculture. We use a stochastic directional distance function framework and a cross-country dataset covering 38 OECD countries. Additionally, we test the heterogeneous impact, considering that regional economic development is a crucial condition for deploying advanced technologies. The findings show that climate-adaptive technological innovation can promote carbon efficiency in agriculture, and this aggregate effect hides significant heterogeneity at different levels of economic development. The higher the economic development level is, the better climate-adaptive technological innovation contributes to improving agricultural carbon efficiency. Then, related policy implications are set forth.

With the rapid development of civil aviation, carbon emissions have brought severe environmental problems. Realizing efficient and sustainable carbon emission reduction is of great significance for achieving green development in civil aviation sector. Therefore, in the process of pursuing civil aviation carbon emission reduction goals, it is necessary to further consider how to achieve emission reduction at the lowest cost. Based on the accurate carbon emission performance evaluation, the carbon abatement cost among different representative airlines have been systematically compared. The main work and findings of this study can be summarized in the following three aspects. Firstly, a new nonparametric shadow price measurement method was constructed based on the Slacks-Based Measurement Data Envelopment Analysis (SBM-DEA). This can better reflect the essence of efficiency evaluation and the calculated shadow price results are more consistent with the real market. Secondly, the average value of carbon emission efficiency has experienced a fluctuating downward trend from 2011 to 2017, indicating that the carbon emission efficiency of global airlines has decreased. Thirdly, the average value of the shadow price is generally between 313.4 and 398.4 dollars/ton, showing an \"up-down-up\" trend, and reaching a peak of 398.4 dollars/ton in 2014. This can provide a basis for low-carbon policy makers in the civil aviation sector, and also provide reference for different types of airlines to achieve low-cost emission reduction.

Agricultural productive service plays an important role in China\'s modernization of agricultural production, and its development is closely related to urbanization. However, its effect on agricultural carbon efficiency has seldom been discussed at different stages of urbanization level. Thus, the paper investigated the relationship between agricultural productive service and agricultural carbon efficiency considering the change in urbanization level, using panel data of China\'s 31 provinces from 2010 to 2020. We find that agricultural productive service can promote agricultural carbon efficiency, and its promotion effect of agricultural productive service will become more powerful with the increase of urbanization level. In addition, its promotion effect is relatively powerful in China\'s eastern provinces, while relatively weak in central and western provinces characterized by low urbanization levels. According to the paper\'s findings, we propose that we should strengthen the development of agricultural productive service in breadbasket provinces and focus on the coordinated development between agricultural productive service and urbanization.

Given that war can have a serious impact on the climate, this article is aimed to discuss the impact of warfare on carbon emissions by examining changes in CO2 before and during the war in Syria based on the kaya constant equation and the LMDI decomposition method. In the decade before the war, population was the largest contributor, making up 32.64% of the total 51.02% increase in carbon emissions. The only factor that offsetting carbon emissions was energy intensity, making a 22.30% curbing effect. In the early stage of the war, carbon emissions decreased by 56.38%, in which per capita GDP contributed 37.55% of the total CO2 decline. Carbon intensive of energy was the only factor promoting the carbon increase with a 4.67% contribution. In the late war, carbon emissions start to resume slow increase with energy intensity and economy turning negative to positive. It can be speculated that the impact of the war on CO2 emissions: (i) in the first years of the war, CO2 would drop significantly at the cost of significant population decline and economic recession, the least desirable and the worst way to reduce carbon emissions. (ii) if evolves into a prolonged war, it would reverse carbon emissions from decline to increase, although the population and the economy are both falling. This research, therefore contends that once war is triggered, there is no other solution to prevent this worst-case scenario of Population Decline - Economic Recession - Increased Carbon Emissions from happening, unless the war is stopped immediately.

Minimizing carbon pollution and fossil fuels is among the most crucial issues in the sustainable development goals (SDGs). However, global environmental concerns have increased since India did not sign the global coal pledge at COP 26. It is therefore a question mark how India will achieve the 2070 carbon-free target with the increasing use of coal and oil. In this contenxt, this work examines the impact of fossil fuel efficiency, structural change, renewable energy consumption, technological innovation, and urbanization on carbon efficiency in India from 1980 to 2019. Employing the dynamic autoregressive distributed lag approach; the study reveals that fossil fuel efficiency, structural change, renewable energy, and technological innovation improve carbon efficiency, while urbanization worsens environmental quality. Based on the study\'s findings, the Indian government should invest more and incentivize technological innovation that supports fossil fuel efficiency and renewable energy deployment to achieve the SDGs.