Emerging Dual‐Channel Transition‐Metal‐Oxide Quasiaerogels by Self‐Embedded Templating

Abstract

The lack of precise control of particle sizes is the critical challenge in the assembly of 3D interconnected transition-metal oxide (TMO) for newlyemerging energy conversion devices. A self-embedded templating strategy for preparing the TMO@carbon quasiaerogels (TMO@C-QAs) is proposed. By mimicking an aerogel structure at a microscale, the TMO@C-QA successfully assembles size-controllable TMO nanoparticles into 3D interconnected structure with surface-enriched carbon species. The morphological evolutions of intermediates verify that the self-embedded Ostwald ripening templating approach is responsible for the dualchannel TMO@C-QA formation. The general self-embedded templating strategy is easily extended to prepare various TMO@C-QAs, including the Co 3 O 4 @C-QA, Mn 3 O 4 @C-QA, Fe 2 O 3 @C-QA, and NiO@C-QA. Benefiting from the unparalleled 3D interconnected network of aerogels, the Co 3 O 4 @C-QA displays superior bifunctional catalytic activities for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), as well as high specific capacity and excellent long-term stability for lithium-ion battery (LIB) anode. A proof-of-concept battery-powered electrolyzer with Co 3 O 4 @C-QA cathode and anode powered by a full LIB with Co 3 O 4 @C-QA anode is presented. The battery-powered electrolyzer made of the state-ofthe-art TMOs can exhibit great competitive advantages due to its supreme multifunctional energy conversion performance for future water electrolysis.

In Situ Grown CoMn2O4 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

“…This performance was compared with those of recently reported oxide-based EWS systems (Figure 7d). [78,85,87,91,92,94,96,[102][103][104][105] The obtained results confirmed that CMO-U@CC exhibited improved electrocatalytic activity with faster kinetics and good stability.…”

“…Figure 4f shows that the OER activity of the CMO-U@CC electrode was superior to those of many outstanding oxide-based electrocatalysts. [19,[40][41][42]45,48,49,[66][67][68][85][86][87] After testing the OER activity, CMO-U@CC was characterized via XPS, XRD, and FESEM analysis (Figure S8a-c, Supporting Information). The XPS characteristic peaks of Co 2p and Mn 2p shifted to higher oxidation states compared with those of CMO-U@CC before OER because of the surface oxidation.…”

“…Figure 5f shows the better HER activity of the CMO-U@CC electrode compared with those of other reported oxide-based electrocatalysts. [70,78,[85][86][87][90][91][92][93][94][95][96][97][98][99] After the HER process, the CMO-U@CC electrode was analyzed via XPS, XRD, and FESEM. The XPS results (Figure S11a-c, Supporting Information) revealed the compositional changes on the surface of the electrocatalyst after the electrocatalytic HER.…”

Superhydrophobic polyvinylidene fluoride/polyimide nanofiber composite aerogels for thermal insulation under extremely humid and hot environment

“…Aerogels are porous materials with nanostructures and exhibit promising potential for heat management due to their high porosity, low density, large specific surface area and low thermal conductivity [10][11][12][13][14]. In the past few decades, a variety of aerogel materials have been suc-cessfully prepared, including graphene [15][16][17], silica [18], carbon nanotubes [19,20] and synthetic polymers [21,22].…”

Superelastic, Fatigue-Resistant, and Flame-Retardant Spongy Conductor for Human Motion Detection against a Harsh High-Temperature Condition

“…The microstructures of MS-(MMT/G) n were accurately controlled by tailoring the deposition numbers. Looking at the morphology of the pristine MS, a 3D open-cell scaffold structure within the MS (Figure b,c) accelerated the penetration of the aqueous dispersion through macropores during the assembly . With an increased assembly number of MMT/G layers, wrinkled structures on the surface gradually came up, while the open-pore structure was maintained (Figure d,f,h).…”