Single-atom catalysts (SACs), with atomically dispersed metal atoms anchored on a typical support, representing the utmost utilization efficiency of the atoms, have recently emerged as promising catalysts for a variety of catalytic applications. The electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination elements. Therefore, engineering the coordination environment near single metal sites, from the first coordination shell to the second shell or higher, would be a rational way to design efficient SACs with optimized electronic structure for catalytic applications. The wide range of coordination configurations, guaranteed by the multiple choices of the type and heterogeneity of the coordination element (N, O, P, S, etc.), further offer a large opportunity to rationally design SACs for satisfactory activities and investigate the structure–performance relationship. In this review, the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was highlighted. Finally, challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more efforts devoted to the further development of single-atom catalysis.
In this paper, a novel event-triggered adaptive fault-tolerant control scheme is proposed for a class of nonlinear systems with unknown actuator faults. Multiplicative faults and additive faults are taken into account simultaneously, both of which may vary with time. Different from existing results, our controller fuses static reliability information and dynamic online information, which is helpful to enhance the fault-tolerant capability. With the aid of an event-triggering mechanism, an actuator switching strategy and a bound estimation approach, the communication burden is significantly reduced and the impacts of the actuator faults as well as the network-induced error are effectively compensated for. Moreover, by employing the prescribed performance control technique, the system tracking error can converge to a predefined arbitrarily small residual set with prescribed convergence rate and maximum overshoot, which implies that the proposed scheme is able to ensure rapid and accurate tracking. Simulation results are presented to illustrate the effectiveness of the proposed scheme. 相似文献