A concise review on the semiconductor-based photocatalytic CO2 conversion based mainly on the leading-edge reports published within the last three years.
Many living organisms track light sources and halt their movement when alignment is achieved. This phenomenon, known as phototropism, occurs, for example, when plants self-orient to face the sun throughout the day. Although many artificial smart materials exhibit non-directional, nastic behaviour in response to an external stimulus, no synthetic material can intrinsically detect and accurately track the direction of the stimulus, that is, exhibit tropistic behaviour. Here we report an artificial phototropic system based on nanostructured stimuli-responsive polymers that can aim and align to the incident light direction in the three-dimensions over a broad temperature range. Such adaptive reconfiguration is realized through a built-in feedback loop rooted in the photothermal and mechanical properties of the material. This system is termed a sunflower-like biomimetic omnidirectional tracker (SunBOT). We show that an array of SunBOTs can, in principle, be used in solar vapour generation devices, as it achieves up to a 400% solar energy-harvesting enhancement over non-tropistic materials at oblique illumination angles. The principle behind our SunBOTs is universal and can be extended to many responsive materials and a broad range of stimuli.
The recent extension of the St€ ober recipe to the synthesis of carbon particles creates tremendous opportunities in the design of novel carbon spheres having micropores, mesopores, or both, as well as composite carbon spheres with incorporated inorganic nanoparticles such as silica and silver.
Two sets of activated carbons have been prepared from waste CDs and DVDs by carbonization and subsequent activation with either KOH or CO 2 . The resulting activated carbons had specific surface area in the range of 500− 2240 m 2 g −1 , total pore volume in the range of 0.18−1.36 cm 3 g −1 , volume of micropores and small mesopores (w < ∼2.9 nm) in the range of 0.17−1.25 cm 3 g −1 , and volume of small micropores (w < ∼1.2 nm) in the range of 0.14−0.71 cm 3 g −1 . Both KOH and CO 2 activation resulted in 5−45-fold improvement in the structural properties, depending on the conditions used. The resulting carbons showed good adsorption properties toward carbon dioxide, hydrogen, and benzene. The best uptakes for these adsorptives were 5.8 mmol g −1 of CO 2 at 0°C and 800 mmHg, 3.3 mmol g −1 of CO 2 at 25°C and 850 mmHg, 13.9 mmol g −1 of H 2 at −196°C and 850 mmHg, and 15.4 mmol g −1 of C 6 H 6 at 20°C and saturation pressure. The excellent adsorption properties of the prepared carbons render them as potential adsorbents in CO 2 capture and storage, VOCs adsorption/separation, and hydrogen storage.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.