Poly(1,5-diaminonaphthalene)-Grafted Monolithic 3D Hierarchical Carbon as Highly Capacitive and Stable Supercapacitor Electrodes

A holistic approach to fabricate a hierarchical electrode that consists of redox-active poly­(1,5-diaminonaphthalene), 1,5 PDAN, uniformly and conformally grafted onto a 3D carbon nanotube (CNT-a-CC) electrode is set forth. The CNT-a-CC electrode was formed by direct growth of high-density CNTs on the surface of every individual microfiber, the constituent of activated carbon cloth (a-CC). Owing to the naphthalene backbone, conformal deposition of 1,5 PDAN on carbon surfaces has been readily attained via electropolymerization. This hierarchical platform with open and continuous nanochannels formed by CNTs coupled with excellent electrical connectivity between CNTs and the polymer provides a reproducible platform for electrochemical investigation. According to multiple sample analyses on CNT-a-CC, the gravimetric capacitance of 1,5 PDAN is up to 1250 F/g, and this value can be maintained up to 100 mV/s. Hierarchical organization provides a specific capacitance of 650 F/g at 2 mV/s at a 1,5 PDAN loading of 2.5 mg/cm2. The conjugated ladder structure of the polymer led to strong π–π interactions between the polymer and CNT-a-CC together with mechanically robust CNT-a-CC. A capacitance retention of 94% for 1,5 PDAN has been obtained after 25,000 cycles at 100 mV/s, a significant cycle stability improvement over conventional conductive polymers such as polyaniline. This new lightweight electrode that seamlessly integrates functional species with nanochannel-like CNT-a-CC opens up a new opportunity to harness electrochemical reactions in the 3D carbon electrode for energy storage and electrocatalysis as well as electrochemical sensing

Amorphous CeO₂–Cu Heterostructure Enhances CO₂ Electroreduction to Multicarbon Alcohols

Electrochemical conversion of carbon dioxide (CO2) gas to value-added chemicals such as multicarbon (C2+) alcohols is a promising and attractive decarbonization strategy. However, there are tremendous challenges in tuning the intrinsic activity and selectivity of the catalysts to produce C2+ alcohols. In this work, we prepared a CeO2–Cu composite catalyst via a combination of metallurgy and dealloying method. The interfacial sites of amorphous CeO2–Cu heterostructure improve the adsorption of key reaction intermediates *CO and promote the C–C coupling. Significantly, they also stabilize *CH2CHO at the bifurcation step, steering the reaction pathway toward the formation of C2+ alcohols over ethylene. The CeO2–Cu catalyst achieves a remarkable faradaic efficiency of 32.9% ± 2.6% for C2+ alcohols at −0.6 V vs RHE. This work demonstrates an effective strategy of improving the intrinsic activity and selectivity of the Cu-based catalysts for the generation of C2+ alcohols