Bifunctional Monolayer WSe₂/Graphene Self-Stitching Heterojunction Microreactors for Efficient Overall Water Splitting in Neutral Medium

Abstract

Developing efficient bifunctional electrocatalysts in neutral media to avoid the deterioration of electrodes or catalysts under harsh environments has become the ultimate goal in electrochemical water splitting. This work demonstrates the fabrication of an on-chip bifunctional two-dimensional (2D) monolayer (ML) WSe2/graphene heterojunction microreactor for efficient overall water splitting in a neutral medium (pH = 7). Through the synergistic atomic growth of the metallic Cr dopant and graphene stitching contact on the 2D ML WSe2, the bifunctional WSe2/graphene heterojunction microreactor consisting of a full-cell configuration demonstrates excellent performance for overall water splitting in a neutral medium. Atomic doping of metallic Cr atoms onto the 2D ML WSe2 effectively facilitates the charge transfer at the solid–liquid interface. In addition, the direct growth of the self-stitching graphene contact with the 2D WSe2 catalyst largely reduces the contact resistance of the microreactor and further improves the overall water splitting efficiency. A significant reduction of the overpotential of nearly 1000 mV at 10 mA cm–2 at the Cr-doped WSe2/graphene heterojunction microreactor compared to the ML pristine WSe2 counterpart is achieved. The bifunctional WSe2/graphene self-stitching heterojunction microreactor is an ideal platform to investigate the fundamental mechanism of emerging bifunctional 2D catalysts for overall water splitting in a neutral medium.

Emerging on-chip microcells in electrocatalysis: functions of window and circuit

“…The authors attributed such a superior performance to the self-stitching heterojunction with a lower contact resistance. 89 Besides the above graphene contact, Cha et al also constructed a WTe 2 –MoS 2 microcell with a WTe 2 metallic contact. As shown in Fig.…”

Te-doped-WSe2/W as a stable monolith catalyst for ampere-level current density hydrogen evolution reaction

“…This includes the exploration of transition-metal carbides, [20][21][22] nitrides, 23,24 sulfides, [25][26][27] oxides 28 and phosphides. [29][30][31] Within the category of catalysts that are free of platinum-group metals, transition-metal disulfides (TMDs), such as WS 2 , 32 WSe 2 33 and WTe 2 , 34 have received significant attention and are regarded as promising electrocatalysts for water splitting. Both theoretical predictions and experimental findings suggest that the HER activity of TMDs primarily stems from their edges rather than their basal planes.…”

Self-supporting FeCoMoP nanosheets for efficient overall water splitting

“…Recently, researchers have shown a preference for non-precious transition metals due to their affordable prices and excellent catalytic properties. 20–22 Transition metal-based oxides, 23,24 hydroxides, 25–28 sulfides, 29–31 phosphides, 32–34 nitrides 35,36 and borides 37,38 were found to be good electrocatalysts for water splitting. Transition metal phosphides (TMPs) are highly conductive, stable, and catalytically active, which has greatly piqued the interest of researchers.…”