Tuning selectivity of electrochemical reactions by atomically dispersed platinum catalyst

Abstract

Maximum atom efficiency as well as distinct chemoselectivity is expected for electrocatalysis on atomically dispersed (or single site) metal centres, but its realization remains challenging so far, because carbon, as the most widely used electrocatalyst support, cannot effectively stabilize them. Here we report that a sulfur-doped zeolite-templated carbon, simultaneously exhibiting large sulfur content (17 wt% S), as well as a unique carbon structure (that is, highly curved three-dimensional networks of graphene nanoribbons), can stabilize a relatively high loading of platinum (5 wt%) in the form of highly dispersed species including site isolated atoms. In the oxygen reduction reaction, this catalyst does not follow a conventional four-electron pathway producing H2O, but selectively produces H2O2 even over extended times without significant degradation of the activity. Thus, this approach constitutes a potentially promising route for producing important fine chemical H2O2, and also offers opportunities for tuning the selectivity of other electrochemical reactions on various metal catalysts.

Recent Progress on Layered Double Hydroxides and Their Derivatives for Electrocatalytic Water Splitting

“…i) The presence of defects in graphene or nanocarbon will efficiently increase the anchor sites that can strongly couple the transitional metal atoms sites by the π–π interaction, finally resulting in fast electron transfer kinetics and excellent stability 150, 152, 153, 154, 155. ii) Theoretical and experimental results further confirm that certain defect sites in graphene can also be served as the active sites for OER and HER, respectively 156, 157.…”

“…To further stabilize and disperse the transition metals on carbon matrix, according to the electronegativity theory, heteroatom‐doped graphene was more conducive to stabilize and disperse metal atoms or 2D nanolayers on graphene 150, 151. Thus, Wei and co‐workers reported a novel composite based on NiFe LDHs and graphene using spatially confined hybridization of nanometer‐sized NiFe LDHs into N‐doped graphene frameworks (nNiFe LDH/NGF) ( Figure 8 A,B) 78.…”

Stabilizing a Platinum1 Single‐Atom Catalyst on Supported Phosphomolybdic Acid without Compromising Hydrogenation Activity

“…On Pt/AC, hydrogen and substrate activation are achieved on aN P surface,followed by surface reaction among adsorbed species. [13] Ad etailed kinetic study,i nsitu spectroscopic analysis,and DFT calculations are needed to reveal the exact working mechanism of the Pt-PMA/ACcatalyst, and to establish the concrete role of PMA in the reaction. Based on DFT calculations,t he substrate adsorption pulls the Pt atom away from the most stable 4-H site (coordination number four) to an off-4-H site leading to reduced oxygen coordination, but the total coordination number remains four (Supporting Information, Table S11 and Figure S18 b-e).…”

The Multifaceted Reactivity of Single‐Atom Heterogeneous Catalysts

“…[10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported (Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27][28] organopolymers, [29,30] nitrides, [31][32][33] and carbides. [10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported (Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27]…”

“…[38] Most reported systems comprise substitutional alloys, which reflects the similarity in the atomic radii. [26][27][28][29][30][31][32] Theh igh level of control over the heteroatom content (for example,nitrogen can be varied from 0-60 wt %) provides immense scope for tuning the density and structure of the coordination sites within functionalized carbons. [39] Furthermore,itisknown that the active metal can go into sites beneath the top-most layer (subsurface) [40] and become inaccessible in amanner similar to bulk atoms in NPs.…”