Achieving decent living standards in emerging economies challenges national mitigation goals for CO2 emissions

Hydrogenation of CO2 for sustainable fuel and chemical production

Catalytic carbon dioxide (CO2) hydrogenation is a potential route for producing sustainable fuels and chemicals, but existing catalysts need improvement. In particular, identifying active sites and understanding the interaction between components and the dynamic behavior of the participant species remain unclear. This fundamental knowledge is essential for the design of more efficient and stable catalysts. Because the nature of the active site (metal, oxide, carbide) is the main factor that determines the catalytic activity of the catalysts, this Review focuses on various types of heterogeneous catalysts that have been recently reported in the literature as efficient for CO2 conversion to C1 [carbon monoxide (CO), methanol (CH3OH), methane (CH4)], and higher hydrocarbons. We focus on establishing key connections between active-site structures and selectivity, regardless of catalyst composition.

Testing the existence of waste Kuznets curve hypothesis in 45 emerging economies: Evidence from an e-waste panel data survey

This study examines the Waste Kuznets Curve (WKC) hypothesis by integrating it with the Tapio decoupling model to explore the relationship between economic development and e-waste imports in 45 emerging economies from 2002 to 2022. The empirical results show that (1) the relationship between economic growth and e-waste imports exhibits an inverted U-shaped curve, with decoupling achieved when GDP per capita exceeds the WKC turning point of $10,755.23; (2) Emerging economies are categorized into six quadrants based on their e-waste decoupling status: high-income non-decoupling, low-income non-decoupling, low-income relative decoupling, high-income relative decoupling, low-income absolute decoupling, and high-income absolute decoupling; (3) Most emerging economies remain in low-income non-decoupling state, with only a few countries like China and Poland achieving high-income absolute decoupling. And (4) tailored policy interventions are crucial for enhancing environmental regulations in low-income non-decoupling countries and improving recycling technologies in high-income non-decoupling countries. This study creates a robust framework for understanding the economic-environmental relationship in emerging economies.

Technological progress and coupling renewables enable substantial environmental and economic benefits from coal-to-olefins

China's growing demand for bulk chemicals and concerns regarding energy security are scaling up coal-to-olefins (CTO) production. Three generations of independent dimethyl ether/methanol-to-olefins technologies have been successively launched with greatly improved production efficiencies. However, to date, widespread concerns regarding the intensive environmental impacts and potential economic risks have not been addressed in the context of this industrialization. Here we show that, through the technological progress from the first to the third generation, life cycle energy consumption, water consumption, and carbon emissions can be reduced to 119.5 GJ/t, 27.6 t/t, and 9.1 t CO2-eq/t, respectively, and human health damage, ecosystem quality damage, and resource scarcity impacts can be decreased by 40.5 %, 50.1 %, and 16.4 %, respectively. This is accompanied by an excellent performance in terms of production cost, net present value, and internal return rate at 792.5 USD/t, 173.4 USD/t, and 19.4 %, respectively. Substantial environmental and economic benefits can be gained by coupling renewables in the form of using green hydrogen from solar and wind power to synthesize methanol. Particularly, life cycle carbon emissions and resource scarcity impacts are reduced by 23.4 % and 22.4 %, respectively, exceeding the reduction in technological progress. However, coupling renewables increases the life cycle energy consumption to 154.5 GJ/t, counteracting the benefits of technological progress. Our results highlight the importance of technological progress and coupled renewables for enhancing the sustainability of the CTO industry.