Mechanistic insights from operando Raman spectroelectrochemistry establishes that synergistic support–catalyst interactions is vital for rational design of electrocatalytic systems to achieve efficient hydrogen generation in alkaline medium.

Anthropogenically triggered escalating contamination of water by heavy-metal ions (As 3+ , Cr 6+ , Cd 2+ , and Hg 2+ ) demands newer and efficient types of adsorbents for their comprehensive scavenging. The wide pH range (pH 2−13) at which such contamination persists makes it challenging to realize a single-step remediation approach. Addressing these escalating demands, a singular adsorbent capable of capturing multiple heavy metal ions with high adsorption capacity across a wide range of pH is herewith reported for sustainable water remediation. Threedimensional dendritic mesoporous nanostructured carbon florets (NCFs) with high specific surface area (936 m 2 /g) and easily accessible open-ended pore structure (1.23 cm 3 /g) achieve highly efficient removal of multiple heavy metal ions (As 3+ , Cr 6+ , Cd 2+ , and Hg 2+ ). The hydrophilic surface of NCF ensures extensive and efficient interfacing with the water feedstock, while its chemical stability ensures its effectiveness as an adsorbent over a wide pH range (pH 2 to pH 13). The synergistic combination of these factors enables excellent adsorption efficiency (AE; ranging from 80% to 90%) and uniformly high adsorption capacity (q e ) toward a variety of heavy-metal ions such as Hg 2+ (395 ± 4 mg/g), Cd 2+ (402 ± 5 mg/ g), Cr 6+ (436 ± 3 mg/g), and As 3+ (412 ± 4 mg/g). Moreover, the gravity-driven purification of water does not demand any external source of electrical power and is scalable for on-site implementation. Facile regeneration of the NCF and its reusability over multiple cycles is also demonstrated for practical and sustainable application in water remediation.

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