Enhanced Visible-Light-Driven Activity of Sodium-, Calcium- and Aluminium-Inserted g-C3N4

g-C3N4 has emerged as a promising low-cost metal free photocatalyst with ideal optical-electronic properties; however, high recombination rate is one of the barriers associated with its low photocatalytic activity. Al and Ca intercalated g-C3N4 photocatalysts with superior visible-light utilization and charge-carrier have been synthesized using one-step thermal condensation method. An enhanced visible-light harvesting capacity due to a red shift in the optical band gap of inserted g-C3N4 photocatalysts was observed. The charge-transfer, its kinetics across the interface and electron-hole pairs separations were systematically investigated using photoelectrochemical measurements. The evaluation of photocatalytic activity of Al and Ca intercalated g-C3N4 through degradation of RhB dye revealed 4.6 and 2.5 fold improvement in performance of g-C3N4. Al intercalated g-C3N4 shows highest photocurrent density, lowest Tafel slope and highest exchange-current density due to least recombination rate of photo generated charge-carriers, facile kinetics and least charge-transfer resistance without use of any noble metal co-catalyst towards oxygen evolution reaction (OER) with excellent stability.