Birmingham team reports porous framework containing 16 metals

University of Birmingham researchers and collaborators reported on October 9 that they had incorporated 16 different metals into a single porous crystal framework. In an announcement distributed by Phys.org, the team also described laboratory tests showing how changing a two-metal mixture within the structure alters its properties, potentially giving researchers greater control over materials designed for gas storage and sensing.

The work involved the universities of Birmingham, Nottingham and Limerick. The announcement identifies a paper by Adnan Ishaq and colleagues in Angewandte Chemie International Edition and names Birmingham professor Neil Champness as its corresponding author.

How the UoB-116 framework holds different metals

The material, called UoB-116, is a metal-organic framework, or MOF. These structures connect metal atoms with organic molecules in an ordered arrangement containing tiny pores. Those internal spaces allow the material to interact with molecules, making porosity an important property for researchers studying gas adsorption.

According to the university announcement, the team first made and structurally characterised 15 individual versions of UoB-116, each containing a different rare-earth metal. Researchers then combined two, four, 12 and 15 metals within the same underlying structure before adding indium to reach 16.

What changing dysprosium and lanthanum controlled

The property measurements described in the announcement focused on changing the balance of dysprosium and lanthanum. Incorporating 16 metals and demonstrating control over properties through a two-metal mixture are separate results; the reported tests do not establish equivalent control over every possible 16-metal recipe.

Increasing the dysprosium content increased the magnetic response, the university reported. Changing its concentration also adjusted the characteristic near-infrared light absorption associated with dysprosium. Increasing the proportion of lanthanum, meanwhile, progressively reduced the measured surface area.

Carbon-dioxide uptake also changed. Under the conditions tested, the all-dysprosium version took up 5.72 millimoles per gram, compared with 1.23 millimoles per gram for the all-lanthanum version, according to the announcement. The figures demonstrate different uptake within this material family, rather than a general improvement from adding more metals.

The announcement does not give the temperature or pressure for those measurements. Without those conditions, the figures do not provide a fair performance comparison with other adsorbents. They also do not establish how UoB-116 would perform in an industrial carbon-capture installation.

In the university’s announcement, Champness said: “Our findings confirm a route toward ‘programmable’ porous materials”. He described the prospect of choosing metal combinations to adjust magnetic, optical, chemical or gas-adsorption behaviour, potentially avoiding the need to invent a new underlying structure whenever different properties are wanted.

Earlier research mapped how metals are arranged

Mixed-metal frameworks have an established research history. A separate study by Zhe Ji, Tong Li and Omar M. Yaghi, published in Science on August 7, 2020, examined MOF-74 containing combinations of cobalt with cadmium, lead or manganese. Its abstract is available through the University of California, Berkeley’s Kavli Energy NanoScience Institute.

Those researchers used atom probe tomography to map metal sequences inside crystals. Depending on the metals and synthesis temperature, they observed random arrangements, short or long runs of matching metals, and insertions. Their findings showed that identifying which metals a framework contains is distinct from identifying their spatial arrangement.

The study examined three crystals for each sequence type. Across the 12 samples, cobalt’s molar fraction varied from 0.4 to 0.9 without changing the sequence type. The authors concluded that MOFs can accommodate metals of different sizes within their rods and support different sequences. This supplies precedent for multimetal design, not independent validation of UoB-116.

What remains unknown about practical applications

The immediate relevance is to researchers designing porous materials. Birmingham identifies gas storage and separation, sensing, catalysis, bioimaging and magnetic materials as areas of MOF research. Those possible uses should not be read as demonstrated applications of UoB-116: the announcement identifies no operational sensor, customer installation or deployment timetable.

It also does not establish production costs, durability or a route to manufacturing at scale. Champness’s proposal is a direction for material design: predicting how strongly particular metals enter a framework could make composition easier to control. How that laboratory flexibility translates into a practical device remains an open question.