“On–off” switch for H₂ and O₂ generation from HCOOH resp. H₂O₂

Abstract

In spite of the numerous advances in the development of H 2 and O 2 evolutions upon water splitting, the separation of H 2 from O 2 still remains a severe challenge. Herein, the novel dual-functional nanocatalysts Pd/ carbon nanosphere (CNS), obtained via immobilization of ultrafine Pd nanoparticles onto CNS, are developed and employed for both selective H 2 generation from HCOOH dehydrogenation and O 2 evolution from H 2 O 2 decomposition. In these reactions, the highest activities for Pd/CNS-800 (i.e., calcinated at 800°C) are 2478 h −1 and 993 min −1 for H 2 and O 2 evolution, respectively. The highly efficient and selective "on-off" switch for selective H 2 generation from HCOOH is successfully realized by pH adjustment. This novel and highly efficient nanocatalyst Pd/CNS-800 not only provides new approaches for the promising application of HCOOH and H 2 O 2 as economic and safe H 2 and O 2 carriers, respectively, for fuel cells, but also promotes the development of "on-off" switch for ondemand H 2 evolution.carbon nanospheres, H 2 generation, O 2 evolution, "on-off" switch, Pd nanoparticles | INTRODUCTIONSince the H 2 -O 2 fuel cell was first discovered by Grove in 1839, 1 it has been widely deemed as the most potential portable and auxiliary power generator because of its merits of green, simple structure, wide operating temperature range, high specific energy, and high energy conversion efficiency. Although H 2 and O 2 are easily produced by water electrolysis, 2-5 it is difficult to find ideal catalysts for this reaction and to separate H 2 from Carbon Energy.

Selective and controlled H2 generation upon additive-free HCOOH dehydrogenation over a Pd/NCS nanocatalyst

“…In the FTIR spectra of Pd/NCSs (Fig. 2b), the absorption peaks at 3232, 2356, 1575 and 1228 cm −1 corresponded to the -OH, C-H, CvC and C-O-C groups, respectively, 53 which were favorable for PdNP stabilization. As presented in Raman spectra (Fig.…”

From sandwich complexes to dendrimers: journey toward applications to sensing, molecular electronics, materials science, and biomedicine

“…195 In the particular case of the nanocatalyzed hydrolysis of bis-boric acid, {B 2 (OH) 4 }, however, both hydrogen atoms of H 2 formed are coming from water, the side product being boric acid, B(OH) 3 . 207,217 The H 2 generation reaction rates can be switched on and off for instance by pH control, 212,215,217 or be boosted by visible-light irradiation, either upon including a semiconductor in the nanocatalyst composite (Mott-Schottky junction at the metal-semiconductor interface), 211 or more efficiently utilizing the Ag or Au plasmon [207][208][209][215][216][217][218][219] or a combination of both the semiconductor and plasmonic effects. 211 The studies of these nanocatalysts bring about considerable knowledge on how the key nanocatalyst hydride are formed and how they reductively eliminate to give H 2 .…”

Bifunctional PdPt bimetallenes for formate oxidation‐boosted water electrolysis

“…Hydrogen (H 2 ), a sustainable and environmentally friendly energy carrier, is a highly promising alternative to fossil fuels. Among various H 2 production methods, water electrolysis (WE) is one of the most promising techniques for high‐purity H 2 production 1–8 . However, the energy conversion efficiency of traditional WE is highly restricted by the sluggish oxygen evolution reaction (OER) at the anode, which expends ca.…”