Nanoporous tin oxide layers were fabricated in NaOH during potentiostatic anodization at a low potential. With increasing potential, the nanochannel became fragmentized and a stacked morphology was formed. The total anodizing current was separated into ionic current and electronic current to explain the various morphologies of nanotubes. The ionic current determines ion migration and oxide growth. The electronic current determines oxygen evolution, porous structure formation, and oxide volume expansion. The continuous decline of the total current–time curve at 8 V was explained by a capacitor model. Through cyclic voltammetry, it was proposed that the stacked morphology exhibits a high specific capacitance (11.36 mF cm–2). Extending the annealing time can increase the crystallinity, thus improving the capacitive performance. The stacked morphology allows electrolytes to permeate the entire portion of the nanochannel more evenly, increasing the effective surface area of the electrode in the electrochemical process and thus improving the capacitive properties. The formation of a stacked morphology is related to the intense release of oxygen gas.

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The impact of economic growth and energy use is still controversial regarding sustainability, and researchers have limited consensus in this regard. Electricity is considered more environmentally friendly compared with direct fossil fuel consumption. However, many developed economies still depend on fossil fuel sources for electricity generation. Therefore, this study attempted to verify the relationship between electricity consumption and carbon emissions in developed economies in the Group of Twenty (G20). Economic growth and foreign direct investment are other important variables for analyzing this relationship. For this purpose, a dataset from 1995–2018 was generated. The study used econometric methods including cross-sectional dependence, cointegration, Fully Modified Ordinary Least Square Dynamic Ordinary Least Square estimators, and the Pair-wise panel Granger causality test to view the latest picture of the relationship between dependent and independent factors. Surprisingly, the outcome of electricity consumption showed a positive relationship with the growth of CO2. This indicates that electricity production is still dependent on sources that help increase CO2 emissions in G20 countries. Furthermore, the outcomes of gross domestic product and its square term confirm the notion of the Environmental Kuznets Curve for these economies. These results suggest that policymakers promote green and clean electricity sources for sustainable economic growth.

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