Light olefins are important feedstocks and platform molecules for the chemical industry. Their synthesis has been a research priority in both academia and industry. There are many different approaches to the synthesis of these compounds, which differ by the choice of raw materials, catalysts and reaction conditions. The goals of this review are to highlight the most recent trends in light olefin synthesis and to perform a comparative analysis of different synthetic routes using several quantitative characteristics: selectivity, productivity, severity of operating conditions, stability, technological maturity and sustainability. Traditionally, on an industrial scale, the cracking of oil fractions has been used to produce light olefins. Methanol-to-olefins, alkane direct or oxidative dehydrogenation technologies have great potential in the short term and have already reached scientific and technological maturities. Major progress should be made in the field of methanol-mediated CO and CO₂ direct hydrogenation to light olefins. The electrocatalytic reduction of CO₂ to light olefins is a very attractive process in the long run due to the low reaction temperature and possible use of sustainable electricity. The application of modern concepts such as electricity-driven process intensification, looping, CO₂ management and nanoscale catalyst design should lead in the near future to more environmentally friendly, energy efficient and selective large-scale technologies for light olefin synthesis.

Pristine, oxidized and defunctionalized carbon nanotubes (CNTs) were studied by Raman spectroscopy, X-ray diffraction, transmission electron microscopy and low temperature nitrogen adsorption. The Raman spectra of the studied samples in the range of 900–1800 cm⁻¹ were deconvoluted into five components to reveal the CNT oxidation mechanism. It was found that the oxidation resulted in the reduction of graphite components and ordering of both the structured and defect part of CNTs. Acid treatment also led to different types of disorders in the surface layers of CNTs. Polyene-type, polyphenylene-type and turbostratic fragments were detected as a result of partial exfoliation. Investigation of defunctionalized CNTs showed the ordering of edge carbon atoms as well as the invariability of the total amount of defects. The study of CNTs as supports for Co-based catalysts revealed a simultaneous decrease in the number of defect fragments and increase in the number of edge carbon atoms during catalyst preparation and reduction.