No abstract

A tin (Sn) nanostructure has been applied to a gas diffusion electrode for the direct electro-reduction of carbon dioxide (CO2) in a zero-gap electrolytic cell.

Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but only a handful have been commercialised and developed as non-food cash crops. One of the reasons why pesticidal plants are failing to deliver new pesticidal products is that they are often not evaluated under field conditions by farmers. Furthermore, many aspects of pesticide use related to environmental safety, such as their impact on beneficial organisms, remain under-evaluated. With a view to overcoming these bottlenecks, extracts made from six abundant weed species found across sub-Saharan Africa (Bidens pilosa, Lantana camara, Lippia javanica, Tithonia diversifolia, Tephrosia vogelii and Vernonia amygdalina) were evaluated in on-station and on-farm trials over two years (2015 and 2016) in two different countries (Tanzania and Malawi) on common bean plants (Phaseolus vulgaris). All plant species offered effective control of key pest species that was comparable in terms of harvested bean yield to a synthetic pyrethroid. Furthermore, the plant pesticide treatments had significantly lower negative effects on natural enemies (hover flies, lacewings, ladybird beetles and spiders). Thus, pesticidal plants were better able to support ecosystem services whilst effectively managing pests. Small holder farmer rankings on the perceived efficacy of the different plant species indicated that T. vogelii was the most preferred and effective, achieving bean yields as good as the synthetic, if not better. As T. vogelii is fast growing with a well-known and understood phytochemistry, it is an excellent candidate for commercial development to supplement pyrethrum production by African small holder farmers.

As global warming directly affects the ecosystems and humankind in the 21st century, attention and efforts are continuously being made to reduce the emission of greenhouse gases, especially carbon dioxide (CO2). In addition, there have been numerous efforts to electrochemically convert CO2 gas to small organic molecules (SOMs) and vice versa. Herein, we highlight recent advances made in the electrocatalytic recycling of CO2 and SOMs including (i) the overall trend of research activities made in this area, (ii) the relations between reduction conditions and products in the aqueous phase, (iii) the challenges in the use of gas diffusion electrodes for the continuous gas phase CO2 reduction, as well as (iv) the development of state of the art hybrid techniques for industrial applications. Perspectives geared to fully exploit the potential of zero-gap cells for CO2 reduction in the gaseous phase and the high applicability on a large scale are also presented. We envision that the hybrid system for CO2 reduction supported by sustainable solar, wind, and geothermal energies and waste heat will provide a long term reduction of greenhouse gas emissions and will allow for continued use of the abundant fossil fuels by industries and/or power plants but with zero emissions.