Desulfurization Efficiency Preserved in a Heterometallic MOF: Synthesis and Thermodynamically Controlled Phase Transition.

Yi Han,Praveen K Thallapally,Simon J Teat,Zimin Nie,Maria L Sushko,Mark E Bowden,Jun Liu,Herbert T Schaef,Lili Liu,Michael A Sinnwell,Quin R S Miller

doi:10.1002/advs.201802056

Abstract

Efficient removal of heterocyclic organosulfur compounds from fuels can relieve increasingly serious environmental problems (e.g., gas exhaust contaminants triggering the formation of acid rain that can damage fragile ecological systems). Toward this end, novel metal‐organic frameworks (MOFs)‐based sorbent materials are designed and synthesized with distinct hard and soft metal building units, specifically {[Yb6Cu12(OH)4(PyC)12(H2O)36]·(NO3)14·xS}n (QUST‐81) and {[Yb4O(H2O)4Cu8(OH)8/3(PyC)8(HCOO)4]·(NO3)10/3·xS}n (QUST‐82), where H2PyC = 4‐Pyrazolecarboxylic acid. Exploiting the hard/soft duality, it is shown that the more stable QUST‐82 can preserve desulfurization efficiency in the presence of competing nitrogen‐containing contaminate. In addition, thermodynamically controlled single‐crystal‐to‐single‐crystal (SC–SC) phase transition is uncovered from QUST‐81 to QUST‐82, and in turn, mechanistic features are probed via X‐ray diffraction, inductively coupled plasma atomic emission spectroscopy, and ab initio molecular dynamics simulations.

Highlights

Efficient removal of heterocyclic organosulfur compounds from fuels (BT)
Novel metalorganic frameworks (MOFs)-based sorbent materials are designed and synthesized with distinct hard and soft metal building units, exhaust gases SOx eventually contribute to the formation of acid rain and harmful particulate matter
A promising alternative method of sulfur mitigation is based on the adsorptive removal of organosulfur compounds, a difficult prospect considering the complitransition is uncovered from QUST-81 to QUST-82, and in turn, mechanistic cated mixture of contaminates in fuels.[7,8,9,10,11]

Summary

Desulfurization Efficiency Preserved in a Heterometallic MOF: Synthesis and Thermodynamically Controlled Phase Transition. Motivated by the coexistence of hard and soft Lewis acid sites in QUST-82, its excellent stability, and high single-component capacity for desulfurization, we further investigated the process of using QUST-82 to remove organosulfur contaminants (DBT) in the presence of competing nitrogen compounds (IND) at equivalent concentrations for the first time In this case, HKUST-1 and CPO-27 (Ni) were selected, both of which can adsorb organosulfur and nitrogen compounds, for comparison (Figure 4). Compared with homometallic-MOFs HKUST-1 and CPO-27 (Ni), QUST-82 maintained relatively high adsorption capacity for DBT from a mixture of DBT and IND These results demonstrate the potential for new porous materials predicted to preserve desulfurization efficiency when competing nitrogen contaminants are present. This dramatic decrease suggests that both Yb and Cu ions can interact with pure IND, whereas in the presence of DBT, the reduction of the accessibility between IND and Cu2+

Experimental Section

Findings

Conflict of Interest