Syngas, a CO and H2 mixture mostly generated from non-renewable fossil fuels, is an essential feedstock for production of liquid fuels. Electrochemical reduction of CO2 and H+/H2O is an alternative renewable route to produce syngas. Here we introduce the concept of coupling a hydrogen evolution reaction (HER) catalyst with a CDots/C3N4 composite (a CO2 reduction catalyst) to achieve a cheap, stable, selective and efficient route for tunable syngas production. Co3O4, MoS2, Au and Pt serve as the HER component. The Co3O4-CDots-C3N4 electrocatalyst is found to be the most efficient among the combinations studied. The H2/CO ratio of the produced syngas is tunable from 0.07:1 to 4:1 by controlling the potential. This catalyst is highly stable for syngas generation (over 100 h) with no other products besides CO and H2. Insight into the mechanisms balancing between CO2 reduction and H2 evolution when applying the HER-CDots-C3N4 catalyst concept is provided.

Electrochemical reduction of CO2 to carbon-containing fuels possesses the potential to solve the environmental issues caused by excess CO2 in the atmosphere. Herein, we introduce a ternary Au-CDots-C3N4 electrocatalyst for efficiently reducing CO2 to CO. The ternary catalyst exhibited significantly enhanced activity and stability for CO2 electroreduction in comparison with pure Au NPs. The Au-CDots-C3N4 electrocatalyst demonstrates a high CO FE of ∼79.8% at −0.5 V and a 2.8-fold enhancement of current density (with the Au loading only 4 wt %) at −1.0 V relative to pure Au NPs. The DFT calculations and experimental observations indicate that the high activity toward CO2RR originates from the synergetic effect among Au NPs, CDots, and C3N4 and the capability of H+ and CO2 adsorption from CDots. The long-term stability tests demonstrate that the electrocatalyst can be used for over 8 h without obvious deactivations and maintained its activity over 60 days under normal conditions.

Two novel Co(II)-cluster-based coordination polymers--namely, [Co5(μ3-OH)2(1,4-ndc)4(bix)2]n (1) and {[Co8(μ3-OH)4(1,4-ndc)6(btp)(H2O)6]·H2O}n (2)--were prepared by hydrothermal reactions of Co(II) perchlorate with 1,4-naphthalenedicarboxylic acid (1,4-H2ndc) and different N-donor coligands (bix = 1,4-bis(imidazol-1-ylmethyl)benzene and btp = 4,4'-bis(triazol-1-ylmethyl)biphenyl). In 1, 10-connected [Co5(μ3-OH)2(COO)8] clusters are extended by the μ4-1,4-ndc(2-) and trans-bix ligands to construct a rare, self-penetrating ile framework that can interestingly be regarded as the cross-link of two interpenetrating 6-connected pcu networks. While for 2, [Co8(μ3-OH)4(COO)12] clusters serve as the 8-connected nodes, which are bridged by the μ4/μ5-1,4-ndc(2-) and trans-btp ligands to afford the highest-connected uninodal self-penetrating (4(20).6(8)) network based on octacobalt clusters. A synthetic and structural comparison of 1 and 2 demonstrates that the features of auxiliary N-donor ligands play a key role in governing the in situ formed clusters and the final 3-D coordination frameworks. Magnetic susceptibility measurements indicate that complex 1 shows an antiferromagnetic interaction between the adjacent Co(II) ions, whereas 2 displays the dominant antiferromagnetic exchanges in 300-50 K and a ferrimagnetic-like behavior at lower temperatures.

Chiral CQDs exhibit strong PL and outstanding enantioselective electrochemical recognition ability. Moreover, chiral CQDs possess independent PL and chiral properties.

An all-carbon memristive synapse is highly desirable for hardware implementation in future wearable neuromorphic computing systems. Graphene oxide (GO) can exhibit resistive switching (RS) and may be a feasible candidate to achieve this objective. However, the digital-type RS often occurring in GO-based memristors restricts the biorealistic emulation of synaptic functions. Here, an all-carbon memristive synapse with analog-type RS behavior was demonstrated through photoreduction of GO and N-doped carbon quantum dot (NCQD) nanocomposites. Ultraviolet light irradiation induced the local reduction of GO near the NCQDs, therefore forming multiple weak conductive filaments and demonstrating analog RS with a continuous conductance change. This analog RS enabled the close emulation of several essential synaptic plasticity behaviors; more importantly, the high linearity of the conductance change also facilitated the implementation of pattern recognition with high accuracy. Furthermore, the all-carbon memristive synapse can be transferred onto diverse substrates, showing good flexibility and 3D conformality. Memristive potentiation/depression was stably performed at 450 K, indicating the resistance of the synapse to high temperature. The photoreduction method provides a new path for the fabrication of all-carbon memristive synapses, which supports the development of wearable neuromorphic electronics.

We have reported a Raman scattering investigation of bismuth ferrite (BiFeO(3)) under high pressure up to 50 GPa. Distinct changes in the Raman spectra show evidence for three pressure-induced structural transitions. The abrupt frequency redshifts of the Raman modes near 300 cm(-1) at around 3 GPa are attributed to the modulation of the FeO(6) octahedral tilts. The disappearance of the modes below 250 cm(-1) at 8.6 GPa, together with the enhancement of the two modes in the range of 300-400 cm(-1), indicate the phase transition from the rhombohedral to orthorhombic symmetry. Afterward, the E-3 and E-4 modes disappear at 44.6 GPa, pointing to the occurrence of the orthorhombic-cubic phase transition, which is consistent with the previous postulate that an orthorhombic-cubic transition takes place across the metal-insulator transition at high pressures.

Data retention was improved in GO-based RRAM through fabricating OCQD–GO nanocomposites, thanks to the increase in the oxygen group migration barrier.

In this paper, a distributed control algorithm is proposed to solve the economic dispatch problem. Without a central control unit, the generators work collaboratively to minimize the generation cost while balancing the supply and demand. The proposed method is based on consensus protocols and the saddle point dynamics. The consensus protocols are employed to estimate the global information in a distributed fashion, and the saddle point dynamics are leveraged to search for the optimal solution of the economic dispatch problem. By utilizing Lyapunov stability analysis, exponential stability of the optimal solution is derived if the capacity limits of the generators are not considered; with the capacity limits, practical stability of the optimal solution is obtained. No global information is needed in the proposed method and the requirement on initial conditions of the state variables is mild. Several case studies on the IEEE 9-bus and IEEE 118-bus systems are presented to demonstrate the effectiveness of the proposed algorithms.