RESUMO
The advancement of a sustainable and scalable catalyst for hydrogen production is crucial for the future of the hydrogen economy. Electrochemical water splitting stands out as a promising pathway for sustainable hydrogen production. However, the development of Pt-free electrocatalysts that match the energy efficiency of Pt while remaining economical poses a significant challenge. This review addresses this challenge by highlighting latest breakthroughs in Pt-free catalysts for the hydrogen evolution reaction (HER). Specifically, we delve into the catalytic performance of various transition metal phosphides, metal carbides, metal sulphides, and metal nitrides toward HER. Our discussion emphasizes strategies for enhancing catalytic performance and explores the relationship between structural composition and the performance of different electrocatalysts. Through this comprehensive review, we aim to provide insights into the ongoing efforts to overcome barriers to scalable hydrogen production and pave the way for a sustainable hydrogen economy.
RESUMO
World's highest arsenic (As) contamination is well-documented for the groundwater system of southwestern region (mainly Jashore district) of Bangladesh, where the majority of inhabitants are underprivileged. To mitigate As poisoning in southwestern Bangladesh, numerous steps have been taken so far by the government and non-governmental organizations (NGOs). Among them, digging deep tube wells and As removal by naturally deposited Fe(OH)3 species are being widely practiced in the contaminated areas. However, these actions have been left unmonitored for decades, making people unaware of this naturally occurring deadly poison in their drinking water. Hence, water samples (n = 63, both treated and untreated) and soil samples (n = 4) were collected from different spots in Jashore district to assess the safety level of drinking water and to understand the probable reasons for high As(III) contamination. About 93.7% of samples were found to contain As(III) above 10 µg/L; among them, 38% contained above 50 µg/L. The study shows that current As(III) removal strategies in the study area are ineffective. In this connection, a simple low-cost As(III) removal adsorbent is proposed that can be prepared with very cheap and locally available materials like iron sludge and charcoal. The adsorbent was characterized in terms of SEM, EDX, and XPS. The optimal dosage of the adsorbent was investigated for real-life application concerning several vital water quality parameters. The Fe-C adsorbent exhibited a maximum As(III) removal efficiency of 92% in real groundwater samples. The study will allow policymakers for informed decision-making regarding water body management as well as enable the local people to avail As-safe water in a way that aligns with their economic factors.
Assuntos
Arsênio , Água Potável , Água Subterrânea , Poluentes Químicos da Água , Purificação da Água , Humanos , Monitoramento Ambiental , Arsênio/análise , Bangladesh , Análise Custo-Benefício , Poluentes Químicos da Água/análiseRESUMO
Organophosphorus Pesticides (OPPs) are among the extensively used pesticides throughout the world to boost agricultural production. However, persistent residues of these toxic pesticides in various vegetables, fruits, and drinking water poses detrimental health effects. Consequently, the rapid monitoring of these harmful chemicals through simple and cost-effective methods has become crucial. In such an instance, electrochemical methods offer simple, rapid, sensitive, reproducible, and affordable detection pathways. To overcome the limitations associated with electrochemical enzymatic sensors, non-enzymatic sensors have emerged as promising and simpler alternatives. The non-enzymatic sensors have demonstrated superior activity, reaching detection limit up to femto (10-15) molar concentration in recent years, leveraging higher selectivity obtained through the molecularly imprinted polymers, synergistic effects between carbonaceous nanomaterials and metals, metal oxide alloys, and other alternative approaches. Herein, this review paper provides an overview of the recent advancements in the development of non-enzymatic electrochemical sensors for the detection of commonly used OPPs, such as Chlorpyrifos (CHL), Diazinon (DZN), Malathion (MTN), Methyl parathion (MP) and Fenthion (FEN). The design method of the electrodes, electrode functioning mechanism, and their analytical performance metrics, such as limit of detection, sensitivity, selectivity, and linearity range, were reviewed and compared. Furthermore, the existing challenges within this rapidly growing field were discussed along with their potential solutions which will facilitate the fabrication of advanced and sustainable non-enzymatic sensors in the future.