MgIn2S4/UiO-66-NH2 MOF-Based Heterostructure: Visible-Light-Responsive Z-Scheme-Mediated Synergistically Enhanced Photocatalytic Performance toward Hydrogen and Oxygen Evolution

Hydrogen and oxygen evolution via photocatalytic watersplittingremains the quintessential alternative to fossil fuels. Photocatalystsmust be sufficiently robust, competent, and productive toward harnessingsunlight in order to utilize the solar spectrum for maximal photocatalyticoutput. Herein, we have fabricated the MgIn2S4/UiO-66-NH2 composite via a facile solvothermal routeand have determined its efficacy toward light-induced H-2 and O-2 generation reactions through water splitting withthe aid of different sacrificial agents. Initially, the formationof pristine and composite materials was ascertained by PXRD, FTIR,etc. Moreover, with the aid of sophisticated morphological characterizationtechniques (FESEM and HRTEM), the intricate interaction between MgIn2S4 and UiO-66-NH2 was revealed. Additionally,the XPS studies suggested the effective interaction between the individualcomponents with binding energy shifting suggesting the transfer ofelectrons from Zr-MOF to MgIn2S4. The PL andelectrochemical aspects supported the effective photogenerated chargesegregation in the prepared composite leading to superior photocatalyticoutputs. Amidst the prepared composites of (3, 5, and 7 wt %) MgIn2S4/UiO-66-NH2, the 5 wt % or UM-2 compositedisplays optimal H-2 and O-2 evolution performancesof 493.8 and 258.6 mu mol h(-1) (4-fold greaterthan for pristine MgIn2S4 and UiO-66-NH2), respectively. The nanocomposite's enhanced performanceis indeed a consequence of the coadjuvant interaction among pristineUiO-66-NH2 and MgIn2S4 componentsthat transpires via the Z-scheme-mediated charge transfer by enablingfacile exciton segregation and channelization. Moreover, the compositeinherited the remarkable framework stability of parent Zr-MOF, andthe MgIn2S4 insertion had a negligible impacton the framework integrity. This work will offer a valuable modelfor developing robust Zr-MOF-based nanocomposite photocatalysts andevaluating their superior performance toward photocatalytic waterredox reactions.

Automated summary

Hydrogen and oxygen generation through photocatalytic water splitting using the MgIn2S4/UiO-66-NH2 composite was studied. The composite showed enhanced photocatalytic performance due to the interaction between MgIn2S4 and UiO-66-NH2 and effective charge separation. Among the various composites, the 5 wt % MgIn2S4/UiO-66-NH2 composite exhibited the highest H2 and O2 evolution rates. This work provides insights for developing robust Zr-MOF-based nanocomposite photocatalysts.