In this report, the ZnO nanoplates with rich porosity have been successfully synthesized using an anion-mediated strategy with a simple hydrothermal method. The morphology, crystal structure, elemental spectra and pore size distribution of this ZnO sample were also determined using various technical methods. Benefiting from the two-dimensional (2D) microstructures and porous architectures for enhanced gas interaction and diffusion, the ZnO nanoplates-based sensor showed a significant response towards formaldehyde vapor in terms of low detection limit and reliable selectivity. This anion-mediated method may act as an efficient strategy for rational design of oxide morphologies tailored for fabricating gas sensors. (C) 2019 Elsevier B.V. All rights reserved.

On basis of the Kirkendall effect, the surface porosity-rich In2O3 microcubes have been successfully prepared through a simple annealing method. Benefiting from the porous surfaces for gas-permeation and strong NO2 adsorption capability, the as-fabricated In2O3 sensor displayed a remarkable response towards NO2 at low temperature (similar to 100 degrees C), including ultrahigh selectivity, excellent stability and low detection limit (similar to 10 ppb). This work offers an effective way to design porous oxide microstructures with enhanced sensing performance. (C) 2020 Elsevier B.V. All rights reserved.

The exploration of highly abundant and available biomass wastes as sustainable precursors through a scalable and cost-effective synthesis strategy is extremely important for novel materials development in energy storage and conversion technologies. Herein, we have successfully fabricated hierarchical micro-/mesoporous carbons (HMMC) from low-cost and eco-friendly agricultural residues via an easy method. The highly hierarchical porous carbons were obtained from rice husk via NaOH-assisted hydrothermal pre-treatment followed by carbonization/activation process. The NaOH-assisted hydrothermal treatment removed ash content and facilitated the development of pores, especially the mesopores, resulting in hierarchical porous carbons with high specific surface area, large pore volume and high ratio (49.3%) of mesopores. These hierarchically structural advantages guarantee the excellent performances of the resultant porous carbons as electrodes for supercapacitors. The rice husk-derived HMMC electrode exhibit a maximum capacitance of 302.2 F g(-1) at a current density of 1 A g(-1 )in a three-electrode system with 6 M KOH as electrolyte, which is significantly better than 193.7 F g(-1) at 1 A g(-1) obtained on rice husk-derived microporous carbons via direct carbonization and activation. Moreover, the NaOH-assisted HMMC electrodes also show good cycle stability. These results demonstrated that NaOH-assisted hydrothermal pre-treatment is a facile and effective way to produce hierarchical porous carbons from natural biomass wastes with improved electrochemical performances for supercapacitors. (C) 2018 The Electrochemical Society.