The fluid catalytic cracking (FCC) process is an alternative olefin production technology, with lower CO₂ emission and higher energy-saving. This process is used for olefin production by almost 60% of the global feedstocks. Different parameters including the operating conditions, feedstock properties, and type of catalyst can strongly affect the catalytic activity and product distribution. FCC catalysts contain zeolite as an active component, and a matrix, a binder, and a filler to provide the physical strength of the catalyst. Along with the catalyst properties, the FCC unit’s performance also depends on the operating conditions, including the feed composition, hydrocarbon partial pressure, temperature, residence time, and the catalyst-to-oil ratio (CTO). This paper provides a summary of the light olefins production via the FCC process and reviews the influences of the catalyst composition and operating conditions on the yield of light olefins.

The production of light olefins, as the critical components in chemical industries, is possible via different technologies. The Fischer–Tropsch to olefin (FTO) process aims to convert syngas to light olefins with high selectivity over a proper catalyst, reduce methane formation, and avoid the production of excess CO₂. This review describes the production of light olefins through the FTO process using both unsupported and supported iron-based catalysts. The catalytic properties and performances of both the promoted and bimetallic unsupported catalysts are reviewed. The effect of support and its physico-chemical properties on the catalyst activity are also described. The proper catalyst should have high stability to provide long-term performance without reducing the activity and selectivity towards the desired product. The good dispersion of active metals on the surface, proper porosity, optimized metal-support interaction, a high degree of reducibility, and providing a sufficient active phase for the reaction are important parameters affecting the reaction. The selection of the suitable catalyst with enhanced activity and the optimum process conditions can increase the possibility of the FTO reaction for light-olefins production. The production of light olefins via the FTO process over iron-based catalysts is a promising method, as iron is cheap, shows higher resistance to sulfur, and has a higher WGS activity which can be helpful for the feed gas with a low H₂/CO ratio, and also has higher selectivity towards light olefins.

It is essential to understand the adsorption of guest molecules on carbon-based materials for both theoretical and practical reasons. It is crucial to analyze the surface properties of carbon-based materials with a wide range of applications (e.g., catalyst supports, hydrogen storage, sensors, adsorbents, separation media, etc.). Inverse gas chromatography (IGC) as a powerful and sensitive technique can be used to characterize the surface physicochemical properties (i.e., Brunauer-Emmett-Teller (BET) surface area, surface energy heterogeneity, heat of adsorption, specific interaction of adsorption, work of cohesion, glass transition temperatures, solubility, and so forth) of various types of materials such as powders, films, and fibers. In this review, the principles, common methods, and application of IGC are discussed. In addition, the examples of various experiments developed for the IGC to characterize the carbonaceous materials (such as carbon nanotubes, graphite, and activated carbon) are discussed.

The current work presents a concept that deals with the production of entropy generated by non-equilibrium processes in consequence of mass and energy transfer. The often used concept of endoreversible thermodynamics is based on the non-realistic conjecture that the entire entropy production is realized at the system boundary. In this contribution, an open system in a thermodynamically non-equilibrium state is assumed. Production of entropy is generated due to non-equilibrium processes accompanied by energy conversion. The steady state of the system is maintained by a negative entropy flux. The conclusions for expansion energy conversion, i. e., thermal machines, confirm the general outcomes of the endoreversible thermodynamics. However, the presented conclusions related to non-expansion energy conversion offer a new perspective on the principle of minimum entropy production and the corresponding stability conditions at steady state. The analysis of the energy conversion in closed cycles is presented for fuel cells, i. e., non-expansion energy conversion. The efficiency of the energy conversion is maximal at zero power output. Moreover, the efficiency of the fuel cells, and consequently the efficiency of all non-expansion energy conversion processes, depends on the load and then the maximal possible efficiency can be determined.

The catalytic performance of a series of La-Fe/AC catalysts was studied for the selective catalytic reduction (SCR) of NO by CO. With the increase in La content, the Fe²⁺/Fe³⁺ ratio and amount of surface oxygen vacancies (SOV) in the catalysts increased; thus the catalytic activity improved. Incorporating the promoters to La3-Fe1/active carbon (AC) catalyst could affect the catalyst activity by changing the electronic structure. The increase in Fe²⁺/Fe³⁺ ratio after the promoter addition is possibly due to the extra synergistic interaction of M (Mn and Ce) and Fe through the redox equilibrium of M³⁺ + Fe³⁺ ↔ M⁴⁺ + Fe²⁺. This phenomenon could have improved the redox cycle, enhanced the SOV formation, facilitated NO decomposition, and accelerated the CO-SCR process. The presence of O₂ enhanced the formation of the C(O) complex and improved the activation of the metal site. Mn@La3-Fe1/AC catalyst revealed an excellent NO conversion of 93.8% at 400 °C in the presence of 10% oxygen. The high catalytic performance of MnO_x and double exchange behavior of Mn³⁺ and Mn⁴⁺ can increase the number of SOV and improve the catalytic redox properties.

This mini-review presents a short account of materials with exceptional activity towards oxygen reduction reaction. Two main classes of catalytic materials are described, namely platinum group metal (PGM) catalyst and Non-precious metal catalyst. The classes are discussed in terms of possible application in low-temperature hydrogen fuel cells with proton exchange membrane and further commercialization of these devices. A short description of perspective approaches is provided and challenging issues associated with developed catalytic materials are discussed.