A. Thomya* and Y. Khunatron
Abstract: This research aimed to study the functional groups of active electrocatalysts on the chlorine-side electrode. Catalyst synthesis involved (RuxCoy)3O4, Co and Ru contents with different Ru/Co molar ratio of 1:9, 2:8, 3:7, 4:6, 5:5. Conditions of catalytic air furnace temperature ranged from 350°C to 500°C. The XRD patterns for catalyst samples confirmed the ruthenium oxide and cobalt oxide phases in the products. The EDS spectra detected ruthenium, cobalt and oxygen in the prepared catalysts. The SEM and TEM images showed more dispersion of catalyst ruthenium oxide on cobalt oxide support surface. Characterization using XRD revealed ~57 nm mean diameter of Co3O4 particle sizes, respectively, while TEM technique gave ~85.93 nm mean diameter of (Ru0.1Co0.9)3O4 particle size. The test results of catalyst properties using XRD, SEM, EDS, TEM, SAD techniques showed the same results. HCl was utilized for RFB by spraying the catalyst material in a range of 0.5-1 M on GDL, the chlorine-side, Carbon paper and Carbon cloth. With Carbon paper that had better discharge voltage efficiency, the 0.5 M treatment generated greatest current density and power density. The catalyst material of 0.5 M on Carbon paper achieved the maximum power density of 19.95 mWcm-2 and current density of 28 mAcm-2 at the voltage efficiency of 69.85%. Hence, the investigation would be beneficial to determine the suitable performance of two-phase flow configuration for redox flow battery with low-cost materials and to gain in-depth understanding of operation characteristics of a redox flow battery using hydrochloric acid as a reactant for new modeling of two-phase flow in cathode.
Keywords: Redox battery, energy storage, hydrochloric acid, catalyst synthesis.
Emily E. Ikhide
Abstract: Achieving economic development alongside environmental sustainability is a major priority of the global development agenda. This relationship between economic development and environmental quality is depicted by the Environmental Kuznets Curve hypothesis. Although there are several studies that have examined the validity or otherwise of the hypothesis, available evidence shows mixed and inconclusive results. In the case of Nigeria, there has also been no attempt to empirically estimate the turning point of the curve. Hence, this study examines the validity of the hypothesis in Nigeria, and estimates the turning point, based on yearly time series data from 1980 to 2016 and the Autoregressive Distributed Lag bound testing approach. The results confirm a long-run relationship between the series and provide evidence in support of the hypothesis in Nigeria. There is a positive sign between Gross Domestic Product (GDP) and CO2 emissions, while a negative sign is found for the square of GDP. However, the linear term is bigger than the non-linear term, signifying that the environmental degradation effect of GDP growth is bigger than the environmental quality enhancement effect. Based on the results, the study recommends that the government develop policies to facilitate the transition from fossil-fuel and diversify the production base of the economy in order to mitigate the environmental effects of economic growth.
Keywords: Energy consumption, economic growth, CO2 emissions, EKC, Nigeria.