Novel sulfur (S) anchoring materials and the corresponding mechanisms for suppressing capacity fading are urgently needed to advance the performance of Li/S batteries. Here, we designed and synthesized a graphene-like oxygenated carbon nitride (OCN) host material that contains tens of micrometer scaled two-dimensional (2D) rippled sheets, micromesopores, and oxygen heteroatoms. N content can reach as high as 20.49 wt %. A sustainable approach of one-step self-supporting solid-state pyrolysis (OSSP) was developed for the low-cost and large-scale production of OCN. The urea in solid sources not only provides self-supporting atmospheres but also produces graphitic carbon nitride (g-C3N4) working as 2D layered templates. The S/OCN cathode can deliver a high specific capacity of 1407.6 mA h g(-1) at C/20 rate with 84% S utilization and retain improved reversible capacity during long-term cycles at high current density. The increasing micropores, graphitic N, ether, and carboxylic O at the large sized OCN sheet favor S utilization and trapping for polysulfides.
Surface defects in relation to surface compositions, morphology, and active sites play crucial roles in photocatalytic activity of graphitic carbon nitride (g-CN) material for highly reactive oxygen radicals production. Here, we report a high-efficiency carbon nitride supramolecular hybrid material prepared by patching the surface defects with inorganic clusters. Fe (III) {PO[WO(O)]} clusters have been noncovalently integrated on surface of g-CN, where the surface defects provide accommodation sites for these clusters and driving forces for self-assembly. During photocatalytic process, the activity of supramolecular hybrid is 1.53 times than pure g-CN for the degradation of Rhodamine B (RhB) and 2.26 times for Methyl Orange (MO) under the simulated solar light. Under the mediation of HO (50 mmol L), the activity increases to 6.52 times for RhB and 28.3 times for MO. The solid cluster active sites with high specific surface area (SSA) defect surface promoting the kinetics of hydroxide radicals production give rise to the extremely high photocatalytic activity. It exhibits recyclable capability and works in large-scale demonstration under the natural sunlight as well and interestingly the environmental temperature has little effects on the photocatalytic activity.
The combination of metal ions with malic acid (hydroxybutane diacid) and 4,4‘-bipyridine ligands under hydro(solvo)thermal conditions has resulted in the formation of three novel coordination polymers, {[M(C4H4O5)(bipy)0.5]·H2O}
n
(M =
CoII (1), NiII (2), 0.3CoII + 0.7NiII (3); C4H4O5
2- = malate dianion, bipy = 4,4‘-bipyridine). The metal ions were interconnected
by α- and β-carboxylates of malate to produce infinite [M(C4H4O5)]
n
layers, which were further pillared by bridging bipy molecules
to form a 3D network. The μ3-malate ligand exhibits a pentadentate coordination mode, with all of the five oxygen atoms participating
in the coordination. The magnetic pathways of three compounds are through M−O−C−O−M with nonplanar skew-skew
conformations; compound 1 shows antiferromagnetic interactions, while 2 is ferromagnetic, due to different electronic configurations
of the metal ions.
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