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Converting CO2 emissions, powered by renewable electricity, to produce fuels and chemicals provides an elegant route towards a carbon-neutral energy cycle. Progress in the understanding and synthesis of Cu catalysts has spurred the explosive development of electrochemical CO2 reduction (CO2RR) technology to produce hydrocarbons and oxygenates; however, Cu, as the predominant catalyst, often exhibits limited selectivity and activity towards a specific product, leading to low productivity and substantial post-reaction purification. Here, we present a single-atom Pb-alloyed Cu catalyst (Pb1Cu) that can exclusively (~96% Faradaic efficiency) convert CO2 into formate with high activity in excess of 1 A cm–2. The Pb1Cu electrocatalyst converts CO2 into formate on the modulated Cu sites rather than on the isolated Pb. In situ spectroscopic evidence and theoretical calculations revealed that the activated Cu sites of the Pb1Cu catalyst regulate the first protonation step of the CO2RR and divert the CO2RR towards a HCOO* path rather than a COOH* path, thus thwarting the possibility of other products. We further showcase the continuous production of a pure formic acid solution at 100 mA cm–2 over 180 h using a solid electrolyte reactor and Pb1Cu. Alloying copper with isolated heteroatoms enables the C protonation of CO2 to HCOO* on activated copper sites, resulting in exclusive electrochemical CO2-to-HCOOH conversion with considerably high activity.

Nanoconfinement provides a promising solution to promote electrocatalytic C-C coupling, by dramatically altering the diffusion kinetics to ensure a high local concentration of C1 intermediates for carbon dimerization. Herein, under the guidance of finite-element method simulations results, a series of Cu2 O hollow multi-shell structures (HoMSs) with tunable shell numbers were synthesized via Ostwald ripening. When applied in CO2 electroreduction (CO2 RR), the in situ formed Cu HoMSs showed a positive correlation between shell numbers and selectivity for C2+ products, reaching a maximum C2+ Faradaic efficiency of 77.0±0.3 % at a conversion rate of 513.7±0.7 mA cm-2 in a neutral electrolyte. Mechanistic studies clarified the confinement effect of HoMSs that superposition of Cu shells leads to a higher coverage of localized CO adsorbate inside the cavity for enhanced dimerization. This work provides valuable insights for the delicate design of efficient C-C coupling catalysts.

Converting CO

The train operation control system in the rail transit has extremely high requirements in terms of reliability and functional safety due to its nature of constant operation, which is often required to achieve the Safety Integrity Level (SIL) 3 or 4. It was concluded in the article that the safety integrity is determined by the systematic failures and random failures of the control system, in which the former will be mitigated by factors of quality management, safety management, technical safety conditions, and the latter requires the achievement of safety target and technical safety conditions to be controlled. The fail-safe concept is the key design principle in the development of the train operation control system. This article summarized the major methods to control the effects of single random faults: Composite Fail Safe, Reactive Fail Safe, and Inherent Fail Safe. The target and computing method of quantified hazardous failure rate is presented for different kinds of control systems, especially for the Composite Fail Safe systems with redundant component, in which a couple of Boolean models are feasible to be applied. The system architectures with 2oo3, as the example, were analyzed. To mitigate the effects of some of multiple faults, the Common-Cause Failure (CCF) needs to be analyzed and the system design should ensure that a multiple failure is not the result of a common cause failure and could only occur by means of a combination of signal random faults. The CCF effect needs to be evaluated especially in the Composite Fail Safe systems, in whichs-factor method would be used for above estimation of the frequency of hazardous failure in this article. The detection of faults is one of key factors during fail-safe design to avoid the effects of single faults as well as the gradually accumulated effects of double or multiple faults in many cases. It turns into the issue of diagnostic methods and coverage of system elements. The diagnostic coverage of an element can be derived considering of the safe failures and hazardous failures. The actions following the detection/diagnosis, especially the retention of safety state, are required as well.