The Ni–Fe layered double hydroxide (LDH) is regarded one of the best catalysts for the oxygen evolution reaction (OER), yet bridging the relationship between the LDH nanostructure and OER performance still remains a big challenge.
The flexible resources of district heating system (DHS) can effectively cope with the fluctuation of photovoltaic (PV) output and improve the security of electric power network. A stochastic optimization method is proposed in this paper for power distribution network with high penetration of PV based on probabilistic forecasting and aggregate flexibility of DHS. Firstly, an adaptive robust optimization framework is used to aggregate the flexible resources of DHS, and the heat output interval is derived to achieve the decoupling of integrated electric-heating system. Then, the PV forecasting result is obtained by nonparametric probabilistic forecasting. Accordingly, PV scenarios with temporal correlation are acquired using Copula formulations. Based on the typical PV scenarios and aggregate flexibility of DHS, the stochastic optimization for combined heat and power dispatch is established. The case study demonstrates the effectiveness and feasibility of the proposed optimization method.
Polymers are important precursors for the fabrication of carbon materials. Herein, halogenated polymers are explored as precursors for the synthesis of high‐quality carbon materials via alkaline dehalogenation. It is found that the halogen elements (F, Cl) connecting to vinylidene units are highly reactive so that dehalogenation can take place a few seconds at room temperature by simple hand grinding in the presence of strong inorganic alkaline. Furthermore, the halogen element‐leaving sites are shown to be susceptible to heteroatom doping (e.g., N doping) to become stable capacitive sites for charge storage (e.g., ions). By using a mixture of NaOEt and KOH as dehalogenation reagents, abundant hierarchical pores (macro/meso/micropores) in the resultant doped carbon matrix for fast mass transportation can be created. Very high capacitance (328 F g −1 at 0.5 A g −1 ) and rate capability (75.3% retention at 50 A g −1 and 62.5% retention at 100 A g −1 ) are observed for the newly developed halogenated polymer‐derived doped carbon materials.
Herein, a strategy for one‐step fabrication of cobalt sulfide/graphene (Co 1− x S/G) nanocomposite as bifunctional catalyst for oxygen catalysis is demonstrated. The one‐step fabrication method involves annealing the mixture of cobalt salt, thioacetamide, and graphene oxide with the assistance of small amount of glycol without any further purification steps. The Co 1− x S/G shows a morphology with small‐sized Co 1− x S nanocrystals strongly and uniformly anchored on the graphene surface. Systematically electrochemical studies demonstrate that the Co 1− x S/G with optimized components shows superior catalytic activities toward oxygen reduction and oxygen evolution, which are comparable or even superior to commercial Pt/C and Ir/C catalysts. As a result, the potential hysteresis of Co 1− x S/G is the lowest among all the samples. The facile operability of the fabrication method and the high bifunctional activity of Co 1− x S/G may pave one practical way for broad applications including fuel cell, metal‐O 2 battery, and water electrolysis.
The wettability of 3D carbon nanotube arrays (CNTAs) was tuned by controlling the nitrogen doping degree, and superhydrophilic nitrogen-doped CNTAs were obtained for anchoring transition metal oxides as bifunctional non-Pt electrocatalysts for high-performance zinc–air batteries.
Monolithic 3D graphene frameworks (GFs) electrode materials have exhibited the great potential for energy storage devices. However, most approaches for fabricating 3D GF require expensive and sophisticated drying techniques, and the current achieved 3D GF electrodes usually hold a relatively low mass loadings of the active materials with low areal capacity, which is not satisfactory for practical application. Herein, a convenient, economic, and scalable drying approach is developed to fabricate 3D holey GFs (HGFs) by a vacuum‐induced drying (VID) process for the first time. This binder‐free 3D HGF electrode with high mass loading can obtain extraordinary electrochemical performance for lithium‐ion batteries (LIBs) due to the 3D holey graphene network owning a highly interconnected hierarchical porous structure for fast charge and ion transport. The HGF electrode with high mass loading of 4 mg cm −2 exhibits superior rate performance and delivers an areal capacity as high as 5 mAh cm −2 under the current density of 8 mA cm −2 even after 2000 cycles, considerably outperforming those of state‐of‐the‐art commercial anodes and some representative anodes in other studies. This facile drying approach and robust realization of high areal capacity represent a critical step for 3D graphene‐based electrode materials toward practical electrochemical energy storage devices.
Singlet oxygen (1O2) is an important reactive oxygen species (ROS) that is intensively involved in natural photochemical and photobiological processes. Herein, selectively lighting up 1O2 is achieved in the aggregation-induced emission (AIE) of electrochemiluminescence (ECL) from the Zn2+-mediated AIE assembly of Au nanoclusters (Zn2+-AIE-AuNCs). Zn2+-AIE-AuNCs can exhibit efficient AIE ECL and photoluminescence (PL) along with 1O2 generation in energy and charge transfer routes, respectively. The AIE ECL of the Zn2+-AIE-AuNCs/tripropylamine (TEA) system in carbonate buffer is located around 703 nm with the dimeric aggregate of 1O2 as an emitter because electrochemically oxidizing coexisted Zn2+-AIE-AuNCs and TEA in carbonate buffer would promote the oxygen vacancy (Ov) of Zn2+-AIE-AuNCs, which could selectively enable the generation of emissive singlet oxygen in the energy transfer route by effectively transferring the energy from excited singlet Zn2+-AIE-AuNCs to the triplet ground state of dissolved oxygen (3O2). No emissive 1O2 is detected via electrochemically oxidizing the Zn2+-AIE-AuNCs in the case without either carbonate buffer or TEA, and the Zn2+-AIE-AuNCs/TEA system can only exhibit AIE ECL around 485 nm with Zn2+-AIE-AuNCs as the emitter in carbonate-free buffers. Photoexciting Zn2+-AIE-AuNCs merely brings out band-gap-engineered AIE PL around ∼485 nm with Zn2+-AIE-AuNCs as the emitter, which manifests that the 1O2 generated in the charge transfer route via photoexciting Zn2+-AIE-AuNCs is un-emissive. This work not only proposes an effective strategy for AIE with 1O2 as an emitter but also opens a promising way to selectively light up 1O2.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)