A critical review of the production and advanced utilization of biochar via selective pyrolysis of lignocellulosic biomass.

The global response to warming of 1.5oC comprises transitions in land and ecosystem, energy, urban and infrastructure, and industrial systems. The feasibility of mitigation and adaptation options, and the enabling conditions for strengthening and implementing the systemic changes, are assessed in this chapter.

Strengthening and Implementing the Global Response

The Sm doped CeO2-TiO2 mixed oxide catalyst, which exhibited excellent activity and tolerance to H2O and SO2 in the NH3-SCR reaction, was synthesized. The reasons for the high activity and SO2 resistance of the catalyst were investigated by a series of characterization. The H2-TPR and O2-TPD results suggested that the reducibility and oxygen storage capacity (OSC) of CeTi catalyst were promoted by the addition of Sm species, which was beneficial for improving the activity of catalyst. The in situ DRIFTS results revealed that the adsorptive ability of NOx species and activation ability of NH3 were enhanced by Sm doping, which was also propitious to enhance the activity. XPS combined with DFT calculated results confirmed that the transfer of electron by Sm2++Ce4+⇌Sm3++Ce3+ circles occurred in the SmCeTi catalyst. The redox circles may be the reason of the good SO2 tolerance of the SmCeTi catalyst, for which suppressed the electron transferring from adsorbed SO2 to Ce4+. Through in situ DRIFTS and TG-DSC results, it can be concluded that the sulphation of catalyst was lowered by samarium doping into CeTi catalyst. Consequently, the SmCeTi catalyst exhibited significant SO2 tolerance ability.

Improved activity and significant SO2 tolerance of samarium modified CeO2-TiO2 catalyst for NO selective catalytic reduction with NH3

Dynamic simulation and assessment of the coupling coordination degree of the economy–resource–environment system: Case of Wuhan City in China

Designing direct Z-scheme photocatalytic systems with core-shell architecture is crucial for effective charge separation towards sustainable photocatalysis. Herein, the core-shell heterojunction photocatalyst consisting of α-Fe2O3 nanoparticle layers encapsulating CeO2 nanotube arrays (Ce@Fe) was successfully synthesized through a simple and feasible strategy. The Ce@Fe heterojunctions exhibit the enhanced solar light scattering and absorption performance from 380 nm to 490 nm. The formed direct Z-scheme band structure between CeO2 and α-Fe2O3 further promotes the efficiency of carrier separation and transfer, and the core-shell nanotube array structure provides high specific surface area for antibiotic adsorption and enhanced light scattering, significantly improving the photoelectrocatalytic activity. Impressively, the unique photoelectrode achieves the highest pollutant removal efficiency of 88.6% for photoelectrocatalytic tetracycline degradation at 1 h under full light irradiation, and affords superior stability and strong alkaline resistance, which is expected to photoelectrocatalytic degrade antibiotics with high efficiency and environmental protection in harsh environment. Furthermore, the novel photoelectrocatalytic mechanism involving transfer behaviors of charge carriers, generation of reactive species, degradation intermediate products of tetracycline can be adopted after growing α-Fe2O3 layers onto CeO2 nanotube arrays, in accordance with direct Z-scheme mechanism.

Construction of core-shell heterojunction regulating α-Fe2O3 layer on CeO2 nanotube arrays enables highly efficient Z-scheme photoelectrocatalysis

In this study, different amounts of Fe and Co species were loaded on activated semi-coke (ASC) using a hydrothermal method for the reduction of NO by CO. The series of prepared catalysts were characterized by SEM, N2 physisorption, ICP, XRD, XPS, H2-TPR, and in situ DRIFTS, as well as ESR and Raman spectroscopy. In addition, the denitration (deNOx) performance and water/SO2 resistance were investigated. The precursor solution with a molar ratio of 0.8:0.2 for Fe:Co (Fe0.8Co0.2/ASC) produced spherical clusters that were uniformly dispersed on the surface. Moreover, Fe0.8Co0.2/ASC exhibited the most effective deNOx activity. The highest deNOx activity for Fe0.8Co0.2/ASC (determined from the characterization) was attributed to the high fraction of Bronsted acid sites, high possibility for the formation of oxygen vacancies, and a strong redox performance. The DRIFTS results suggested a possible mechanism involving the adsorption of NO on the Fe0.8Co0.2/ASC surface, followed by its transformation to nitrates or nitrite/nitro species. At low temperatures ( 200 °C), the coordinated nitrates and CO species on the surface reacted with the produced CO2 and N2. The effects of water and SO2 on the deNOx performance were examined. In the presence of only water, the deNOx performance decreased because of the competitive adsorption with NO, and in the presence of only SO2, reversible deactivation was observed; however, if both water and SO2 were present, irreversible catalyst deactivation was observed.

Investigation on Fe-Co binary metal oxides supported on activated semi-coke for NO reduction by CO

Copper catalysts supported on co-synthesised Fe2O3 and CeO2 mixed metal oxide support (Cu/CeO2-Fe2O3, Cu/CF for short, CF as the support) were prepared for NO reduction by CO. Cu/CF catalysts showed better catalytic performance at 100–200 °C than samples of Cu/CeO2 and Cu/Fe2O3 which were supported on single metal oxide. The interaction of Fe and Ce could enhance the catalytic activity. The catalysts were characterized by N2 adsorption, TEM, XRD, Raman, XPS, H2-TPR, EPR, and in situ DRIFT. Cubic CeO2 was found to serve as the lattice framework in the support of mixed oxides. Fe2O3 phase are mainly formed on the surface of CeO2 lattice in the CF involved samples, and the ‘topped’ Fe2O3 phase on the CeO2 crystals may facilitate the incorporation of iron atoms into CeO2 lattice. The high fraction of oxygen vacancy in catalyst Cu/CF may also facilitate the redox cycle of oxygen during catalytic reactions. The interaction of Cu oxide with CF support favourably promotes the reduction of Cu oxide and diffusion of surface oxygen species at low temperatures. During the NO + CO catalytic reactions, CeO2 serves as the storing sites of carbonate and enhances CO oxidation, Fe2O3 serves as the storing sites of nitrites and nitrates and facilitates NOx adsorption, and impregnated copper helps to convert inactive nitrites into active intermediates for NO + CO reaction. The promoted adsorption and conversion of both carbonates and nitrite/nitrates over catalyst Cu/CF could be the reason of its excellent catalytic activity for NO + CO reaction.

NO reduction by CO over copper catalyst supported on mixed CeO2 and Fe2O3: Catalyst design and activity test

A review of recent advances in selective catalytic NOx reduction reactor technologies

Coordinated development of energy, economy and environment subsystems - A case study

The adsorption performance and catalytic activity of Fe/ZSM-5 for the selective catalytic reduction (SCR) of NOx with propylene were studied in a fixed bed reactor using model flue gases. The Fe/ZSM-5 catalyst showed reasonable NOx adsorption capacity, and the adsorption performance is closely related to the particle size and the structure of the catalyst support. The increase of O2 concentration significantly enhanced the adsorption of NOx on Fe/ZSM-5, and CO2 in the flue gas exhibited certain negative impact on the adsorption capacity, while H2O showed little effect. HC-SCR experiments showed that Fe/ZSM-5 catalyst was sensitive to the reaction temperature and space velocity, and exhibited acceptable activity when O2 concentration was controlled at a low level. Water in the flue gas was found to slightly enhance the reactivity of Fe/ZSM-5, while the presence of CO2 showed little effect.

Xingxing Cheng

Papers

Investigation on Fe-Co binary metal oxides supported on activated semi-coke for NO reduction by CO

NO reduction by CO over copper catalyst supported on mixed CeO2 and Fe2O3: Catalyst design and activity test

A review of recent advances in selective catalytic NOx reduction reactor technologies

Coordinated development of energy, economy and environment subsystems - A case study

Effects of O2, CO2 and H2O on NOx adsorption and selective catalytic reduction over Fe/ZSM-5