Coordinated reduction of CO_(2) emissions and environmental impacts with integrated city-level LEAP and LCA method: A case study of Jinan, China

The evaluation of the efficiency and feasibility of energy transition and air pollution control at the city level is one of the key points in addressing environmental problems and achieving the goals of CO_(2) emission reduction and carbon neutrality in China. In this study, an integrated method is developed on the basis of the Low Emissions Analysis Platform (LEAP) and life cycle assessment (LCA). The energy demands and environmental co-benefits in Jinan, one of the low-carbon city pilots in China, are quantitatively evaluated under three policy scenarios: low-carbon (LC) policy scenario, pollution control (PC) policy scenario, and deep-level cut of CO_(2) emissions (DCC) scenario from 2016 to 2050. From 2016 to 2030, the PC policies would be more powerful than the LC policies in terms of energy demand decrease. From 2030 to 2050, the LC policies would be more efficient than all the other policies. Promoting energy-saving buildings in the LC scenario would contribute to the continual decline in energy demands. In the DCC scenario, CO_(2), PM_(2.5), PM_(10), CO, NO_(X) and SO_(2) emissions would decline by more than 71.4% relative to the records in 2016. Global warming potential, human toxicity potential, photochemical ozone creation potential, particulate matter formation potential, and acidification potential would also decrease by 81.8%–88.5%. On the basis of the integrated city-level LEAP and LCA method, this study quantifies the various environmental impacts of urban decarbonization policies and provides science-based references for urban low-carbon transformation.

Regulating single-atom Mn sites by precisely axial pyridinic-nitrogen coordination to stabilize the oxygen reduction

Designing single-atom catalysts for oxygen reduction reaction(ORR)are fashionable but challenging to boost the zinc-air battery performance.Significantly enhanced ORR activity by manganese(Mn)singleatom catalysts can be achieved by accurately regulating the coordination number of isolated Mn atoms.Theoretical calculations indicate that the single Mn-N5sites possess lower free energy barrier and higher oxygen adsorption performance than single Mn-N4sites to accelerate the ORR kinetics.Target to it,here we synthesize an atomically dispersed Mn-N5catalyst by precisely axial coordination of pyridinic-N doped into two-dimensional(2D)porous nanocarbon sheets(~3.56 nm thickness),which reveals outstanding catalytic activity and ultrahigh stability for the ORR in zinc-air battery owing to the inhomogeneous charge distribution of Mn-N5sites compared to the conventional single-site Mn-N4catalyst and Pt/C.This work gives a new strategy for in situ regulating the electronic structure of metal single-atoms and further promoting the overall ORR performance in energy systems.