Dry reforming of methane (DRM) offers an attractive solution for the high-value utilization of two primary greenhouse gasses, methane and carbon dioxide, but its industrial applications are hindered by the net carbon dioxide–positive emissions resulting from substantial energy consumption. Here, we developed an electrified technology by passing electric current through a conductive catalyst constituting nickel and lanthanum(III) oxide cosupported on activated carbons, reaching thermodynamic equilibrium conversions and sustaining for at least 120 hours. Notably, the energy efficiency (2.976 millimoles per kilojoule) exceeds all the previously reported values, enabling net carbon dioxide–negative emissions powered by common sustainable electricity. An electrically driven release of lattice oxygen bridges the decomposition of the lanthanum oxycarbonate intermediate generated from carbon dioxide activation and the reduction of the resultant nickel oxide species by deposited carbon from methane dissociation, thus inhibiting excessive nickel oxidation and lanthanum(III) oxide carbonatation. The electrified approach would make DRM a true pathway mitigating overall carbon footprint and combating global warming.

Small porous Cu-SSZ-13 catalysts have recently been commercialized for the selective catalytic reduction of NO_x with ammonia (NH₃-SCR) on diesel vehicles. Unfortunately, the conventional Cu-SSZ-13 catalyst still confronts the challenge of diffusion limitations, which represent a major obstacle that reduces the catalyst’s SCR performance. Herein, a hierarchically porous SSZ-13 zeolite was synthesized via a trans-crystallization method assisted by the use of carbon black as a hard template in a short synthetic period, and the corresponding Cu-SSZ-13 catalysts with mesopores exhibited improved low-temperature activity and hydrothermal stability when compared with their microporous counterpart. A series of characterizations revealed that the mesopores are conducive to an increase in Cu loading while helping to stabilize the CHA structure and maintain the Cu species in their ionic form. More importantly, intra-particle diffusion limitations are reduced via the introduction of the mesopores owing to the shortened diffusion path inside the SSZ-13 zeolite, thus not only enhancing the active sites’ accessibility but also promoting the diffusion of the reactants and products. This work contributes to the design and synthesis of a high-performance Cu-SSZ-13 zeolite SCR catalyst for the removal of NO_x emitted from diesel vehicles.

Nitrogen oxides (NO_x), which are the major gaseous pollutants emitted by mobile sources, especially diesel engines, contribute to many environmental issues and harm human health. Selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) is proved to be one of the most efficient techniques for reducing NO_x emission. Recently, Cu-SSZ-13 catalyst has been recognized as a promising candidate for NH₃-SCR catalyst for reducing diesel engine NO_x emissions due to its wide active temperature window and excellent hydrothermal stability. Despite being commercialized as an advanced selective catalytic reduction catalyst, Cu-SSZ-13 catalyst still confronts the challenges of low-temperature activity and hydrothermal aging to meet the increasing demands on catalytic performance and lifetime. Therefore, numerous studies have been dedicated to the improvement of NH₃-SCR performance for Cu-SSZ-13 catalyst. In this review, the recent progress in NH₃-SCR performance optimization of Cu-SSZ-13 catalysts is summarized following three aspects: 1) modifying the Cu active sites; 2) introducing the heteroatoms or metal oxides; 3) regulating the morphology. Meanwhile, future perspectives and opportunities of Cu-SSZ-13 catalysts in reducing diesel engine NO_x emissions are discussed.

Since 2002, we have been carrying out programs in developing Saturated Iron-core Superconducting Fault Current Limiters (SISFCLs). Innovative technologies were adopted in designing the iron-core and the magnetization circuit, making our SISFCL more efficient, useful, and reliable. With our technology, a 35 kV SISFCL with dry-type electrical insulation and a 220 kV SISFCL with oil electrical insulation were manufactured and installed for live-grid operation in 2008 and in 2012 respectively. Operation data and test results show that the performances of the devices meet design expectations and utility's needs. Our SISFCL is applicable for both transmission and distribution networks and can satisfy a wide range of fault current limiting impedance requirements.