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Hydrogen production through electrolyzing water can transfer the energy from solar energy, wind energy and other sustainable energy to hydrogen, a clean energy carrier with high energy density. The NiP₂ has attracted much attention as a cheap electrocatalyst with high catalytic performance for hydrogen evolution reaction (HER). In this paper, the adsorption energy, Gibbs free energy and exchange current densities at different sites on NiP₂ (100) surface are calculated. On this basis, the effect of strain and doping on the HER catalytic performance of NiP₂ are studied. By calculation, we find that when H is adsorbed on the top site of P atom on NiP₂ (100) surface, the exchange current density is the closest to the top of volcanic curve, so the top site of P atom on NiP₂ (100) surface is the catalytic active site. The effect of doping and strain on the catalytic performance of NiP₂ are analyzed. 1) According to the range of strain produced by the common experimental technology, the effects of 1% and 3% tensile and compressive strain are calculated. It is found that 1% compressive strain can improve the catalytic performance of NiP₂, while when 3% compressive strain or a 1% or 3% tensile strain is applied, the catalytic performance of NiP₂ is not enhanced. 2) The effects of doping transition metal elements (Co, Fe, Mn, Mo, Cu, W, Cr) and non-metallic elements (N, C, S) on the catalytic performance of NiP₂ are calculated. It is found that doping non-metallic element S can significantly improve the HER catalytic performance of the top site of P atom, while the doping of transition metal elements Mn, Mo, W, Co, Cr, Fe, Cu and non-metallic elements N, C have no effect on this site. The doping of transition metal element (catalytic activity: Mn > Mo > W > Co > Cr > Fe > Ni) Mn can make the catalytic performance of inactive site improved to that of the active site, thus indirectly improving the catalytic performance of NiP₂. Our work reveals the micro mechanism of the effect of doping and strain on the performance of HER electrocatalyst, which provides a new perspective for designing the high performance HER electrocatalyst.

China has a considerable impact on climate change, as it is the world’s largest developing country. Its carbon emissions are also a global concern. This research employed a multi-region input–output model to estimate the local emission effect and the regional spillover effect caused by the demand for intermediate and final products, to analyze the interregional flow of carbon emissions, and to identify the main industries causing domestic carbon emissions in China from 2007 to 2012. A structural path analysis model was used to evaluate the contribution of different factors and demand types to changes in carbon emissions. The following findings were obtained in this study: (1) The regional spillover effect of carbon emissions driven by domestic demand is characterized by inland provinces’ demand leading to emissions in coastal provinces. (2) Electricity, nonmetallic minerals, and metals are the key industries for carbon emissions. (3) The results of the SDA indicate that the scale effect is the main driving force for the growth in carbon emissions caused by domestic demand in China. Fixed capital formation is the most critical demand factor influencing carbon emissions. This study provides new insights into the characteristics of regional emission transfer in China. The conclusion of this paper is helpful to China in achieving carbon peak and carbon neutrality.