Development of carbon dots supported on Zr-MOFs nano-composites for effective oxygen evolution reaction

Efficient hydrogen generation from water splitting is a key component of the hydrogen economy. It has been extensively researched for decades how electrochemically splitting water using electrocatalysts might provide a sustainable and environmentally friendly hydrogen energy source. Sluggish kinetics of the oxygen evolution reaction (OER) hinders the process of overall water splitting. Although metal-organic frameworks (MOFs) are attractive for generation of effective OER electrocatalysts, their activity is significantly hindered by their inherent lower conductivity. Here, we demonstrate a Zr-MOF-based composite with carbon dots (CDs) in order to increase their OER activity. Its exceptional morphology with higher porosity and greater surface area results in enhanced electrochemical activity. It reveals tremendously low onset potential, i.e., 1.40 V vs. RHE, and a remarkably small overpotential of 1.45 V vs. RHE to attain benchmark current density. It exhibited a minimal Tafel value of 37 mV/dec, conquering state-of-the-art catalysts for OER. The fabricated electrocatalyst demonstrated a lower charge transfer resistance (R_ct) of 0.248 Ω, with exceptional durability for about 20 h in chronoamperometric studies and for up to 1500 CV cycles. All these results demonstrated that as-fabricated Zr-MOF-based composite is a probable and potential candidate for OER.