The team, led by Xiaoxue Liu, Yazhong Chen, Haifeng Wu, Xiaolin Sun, Bing Li, Xueping Wu, and Xianlong Zhang, prepared a family of catalysts labeled Mnx/SFCCC, where x denotes the weight percent of manganese loaded onto the support. The support, SFCCC, is spent fluid catalytic cracking catalyst, the used zeolite-based material that petroleum refineries discard by the ton once it loses activity in cracking units. Rather than letting this spent material go to landfill, the researchers repurposed it as a scaffold for manganese oxide, dramatically cutting the cost of the final catalyst while giving the waste a second life.

Because the way a catalyst is made can matter as much as what it is made of, the group synthesized their materials by three distinct routes: in situ deposition, precipitation-deposition, and incipient wetness impregnation. In situ deposition forms manganese oxide directly on the support surface under reaction conditions, precipitation-deposition builds the oxide through controlled precipitation onto the support, and incipient wetness impregnation soaks the support pores with a precursor solution before drying and calcination. Each technique distributes the manganese differently, and those differences in dispersion, particle size, and surface chemistry translate directly into differences in catalytic behavior.

To understand why one preparation outperformed the others, the researchers characterized their samples with an extensive toolkit. Low-temperature nitrogen adsorption measured surface area and pore structure, X-ray diffraction and scanning electron microscopy probed crystalline phase and morphology, hydrogen temperature-programmed reduction and oxygen temperature-programmed desorption assessed redox behavior and oxygen mobility, and X-ray photoelectron spectroscopy and electron paramagnetic resonance revealed surface oxidation states and defect sites. Inductively coupled plasma optical emission spectrometry confirmed the actual manganese loading in each batch. Together these measurements connected synthetic route, physical structure, and chemical functionality in a single coherent picture.

The performance results were striking. The catalyst prepared by in situ deposition with 14 weight percent manganese, Mn14/SFCCC-SP, delivered the best outcomes of the entire series. In static testing with an initial formaldehyde concentration of 4.5 parts per million, it removed 90.0 percent of the gas within 120 minutes at room temperature. Under dynamic conditions in a fixed-bed reactor, more representative of a real air purification device, it achieved greater than 95 percent removal at a gas hourly space velocity of 34,000 milliliters per gram per hour with an initial formaldehyde concentration of 7.0 parts per million. The catalyst also showed good stability and consistent performance across repeated use cycles, a critical requirement for any practical air-cleaning product.

The characterization data explain this superiority. Mn14/SFCCC-SP possesses a high specific surface area of 158 square meters per gram together with substantial pore volume, providing abundant sites where formaldehyde molecules can adsorb and react. The spent FCC support itself contributes porosity and a chemically heterogeneous surface, while the in situ deposition method deposits manganese oxide in a highly dispersed, well-contacted form rather than in bulky crystalline aggregates that bury active sites. High dispersion means more manganese atoms sit at the interface where gas molecules can reach them.

Even more important is the catalyst’s oxygen chemistry. X-ray photoelectron spectroscopy and electron paramagnetic resonance showed that the best sample carries a high concentration of surface-adsorbed oxygen species and oxygen vacancies, defects in the oxide lattice where an oxygen atom is missing. These vacancies are generated through the Mn4+/Mn3+ redox couple: when manganese cycles between its +4 and +3 oxidation states, lattice oxygen is consumed and replenished, continuously creating and refilling vacancy sites. The redox couple also gives the material good low-temperature reducibility, meaning it can activate oxygen molecules from air and transfer them to adsorbed formaldehyde even without external heating.

This mechanism sits at the heart of why the result matters. In the Mars-van Krevelen-type process that governs manganese oxide catalysts, formaldehyde first adsorbs on the surface, reacts with reactive oxygen to form intermediates such as formate and dioxymethylene species, and is finally oxidized to carbon dioxide and water, while gas-phase oxygen refills the vacancies the reaction consumed. A catalyst rich in vacancies and easily exchanged oxygen keeps this cycle running briskly at ambient temperature. The Hefei team’s evidence that the Mn4+/Mn3+ redox couple generates the vacancies that drive the reaction provides a clear design rule: maximize the interfacial contact between well-dispersed manganese oxide and a porous, defect-friendly support.

The choice of support is what makes the work economically compelling. Spent FCC catalysts are generated worldwide in enormous quantities, and disposal is an ongoing cost and environmental burden for refiners. Previous studies have explored supports ranging from activated carbon and diatomite to palygorskite, halloysite, and montmorillonite, often with excellent catalytic results but at a price that hinders scale-up. Using a pre-existing industrial waste stream as the support flips the cost equation: the raw material is essentially free, widely available, and already engineered to have favorable particle properties from its first life in the refinery. The authors specifically highlight that SFCCC was chosen to significantly reduce the cost of the catalyst, and the strong performance of the in situ deposition route shows that low cost need not come at the expense of activity.

For consumers, the implications are tangible. A room-temperature formaldehyde oxidation catalyst that maintains over 95 percent removal under demanding flow conditions could be integrated into air purifiers, ventilation systems, and building materials, continuously eliminating a carcinogenic pollutant rather than temporarily trapping it. Because the active component is abundant manganese rather than precious platinum, silver, or gold, the materials cost of deployment falls by orders of magnitude. And because the support is recycled refinery waste, the catalyst’s own footprint shrinks, turning one industrial waste problem into a solution for another environmental one. The study, published in Catalysis Letters, demonstrates that careful attention to preparation method, manganese loading, and support chemistry can transform a discarded powder into a high-performing environmental catalyst. As indoor air quality gains attention as a public health issue, such cheap, stable, and efficient room-temperature catalysts may soon move from the laboratory bench into the devices quietly cleaning the air in homes, offices, and schools.

Subject of Research: Room-temperature catalytic oxidation of formaldehyde using manganese oxides supported on spent FCC catalyst

Article Title: Room-Temperature Catalytic Oxidation of Formaldehyde Over Manganese Oxides Supported on SFCCC Prepared via Different Methods

Article References: Liu, X., Chen, Y., Wu, H., Sun, X., Li, B., Wu, X., & Zhang, X. (2026). Room-Temperature Catalytic Oxidation of Formaldehyde Over Manganese Oxides Supported on SFCCC Prepared via Different Methods. Catalysis Letters, 156(10), Article 279. https://doi.org/10.1007/s10562-026-05513-2

Image Credits: AI Generated

DOI: 10.1007/s10562-026-05513-2

Keywords: formaldehyde, manganese oxides, spent FCC catalyst, room temperature catalysis, oxygen vacancies, indoor air purification, catalyst preparation, redox couple, waste recycling, Catalysis Letters, Room-Temperature, Catalytic

Quantum computers derive their power from entanglement, the uniquely quantum correlation that links the states of qubits so that they can no longer be described independently. In most of today’s architectures, creating entanglement among many qubits is a serial affair: a two-qubit gate links one pair, then another pair, then another, with each operation taking time and introducing its own quota of imperfection. For a register of even modest size, the number of sequential gates required to generate a genuinely multipartite entangled state grows quickly, and every additional step eats into the fragile window before decoherence destroys the quantum information altogether.

The new experiment tackles this bottleneck at its root. Instead of stitching together pairwise interactions, the researchers engineered a single gate that acts on four qubits simultaneously within a spin register that functions at ambient conditions. Room-temperature operation is itself a notable achievement, because most leading quantum computing platforms, including superconducting circuits and trapped ions, demand elaborate cryogenic or ultra-high-vacuum environments. A register that can be manipulated on a benchtop, without dilution refrigerators, dramatically lowers the barrier to scaling and integration, and opens the door to quantum devices that resemble conventional electronics far more closely than the laboratory behemoths of current-generation hardware.

Spin registers of the kind used here rely on well-protected quantum states associated with electron or nuclear spins in solid-state defects. These systems have long been attractive to quantum engineers because their spin states can be initialized, manipulated with microwave or optical pulses, and read out with laser-based techniques, all while remaining comparatively insensitive to thermal noise. The central challenge has always been the coupling between qubits: interactions in such registers are often mediated through a shared resource, which makes it difficult to address pairs selectively without disturbing the rest of the register. The demonstration of a clean, parallelized multi-qubit gate shows that this mediation can be turned from a liability into an asset, with the shared interaction structure harnessed to entangle several qubits in one stroke.

The speed advantage reported by the team is not merely a matter of convenience. In quantum error correction and in most quantum algorithms, the ratio of gate time to coherence time is one of the fundamental figures of merit that determines whether a computation can be completed before the quantum states decay. A four-qubit gate executed in the time of roughly a single pairwise operation, and ten times faster than the equivalent four-gate sequence, means that substantially deeper circuits can be run within the same coherence budget. The reduction in accumulated errors compounds this benefit: if each two-qubit gate carries even a small error probability, replacing four sequential operations with one parallel operation cuts the total error budget nearly in half before improvements in the gate itself are even considered.

Multipartite entanglement, in which three or more qubits share correlations that cannot be reduced to pairwise links, is a resource in its own right. It underlies measurement-based quantum computing, in which a large entangled state is prepared in advance and computation proceeds by single-qubit measurements, as well as quantum error-correcting codes, quantum teleportation networks, and metrology schemes that squeeze below the standard quantum limit. Generating such states efficiently, and at room temperature, could therefore benefit far more of the quantum technology stack than computation alone. A scalable source of multipartite entanglement that does not require cryogenic hardware would be directly relevant to quantum sensors deployed in the field and to compact quantum communication nodes.

The parallelized approach also speaks to a broader architectural question in quantum engineering: whether future processors should be built from networks of pairwise-coupled qubits or from registers whose qubits interact collectively through a common mediator. The two strategies carry different trade-offs. Pairwise architectures offer fine-grained control and map naturally onto established gate models, but they demand ever more elaborate wiring and calibration as systems grow. Collectively mediated registers, by contrast, can offer intrinsically parallel operations and simpler connectivity graphs, at the cost of more complex pulse engineering to ensure that unwanted crosstalk is suppressed. By demonstrating a high-fidelity four-qubit gate in the collective setting, the new work strengthens the case that register-based architectures deserve a central place in the scaling roadmap.

Room-temperature operation carries particular weight for real-world deployment. Cryogenic infrastructure is expensive, power-hungry, and bulky, and it constrains where quantum processors can be physically located. Systems that operate at ambient conditions can be miniaturized more aggressively, integrated into photonic or electronic packages, and deployed in settings ranging from data centers to medical imaging suites to autonomous platforms. Spin-based registers have already been proposed as quantum memories that link flying qubits such as photons, and a fast, parallel entangling gate makes such memories far more capable, since entanglement between memory qubits can be established on demand without consuming the register’s limited coherence time on long gate sequences.

As with any first demonstration, the path from a four-qubit parallel gate to fault-tolerant computation remains long. Scaling to larger registers will require maintaining gate fidelity as more qubits share the mediator, refining pulse sequences to suppress crosstalk, and integrating high-efficiency readout. Nevertheless, the result establishes a concrete benchmark: a single gate producing genuine multipartite entanglement, faster and more cleanly than the serial alternative, on hardware that needs no cooling. If the parallel-gate paradigm can be extended to larger registers and combined with error correction, it may prove to be one of the key simplifications that finally brings room-temperature quantum processors out of the laboratory and into everyday technological use.

Subject of Research: A parallelized four-qubit entangling gate demonstrated on a room-temperature quantum spin register

Article Title: Single-gate, multipartite entanglement on a room-temperature quantum register

Article References: Minnella, J. D., Ouellet, M., Klein, A. R., & Bassett, L. C. (2026). Single-gate, multipartite entanglement on a room-temperature quantum register. Nature Nanotechnology. https://doi.org/10.1038/s41565-026-02254-6

Image Credits: AI Generated

DOI: 10.1038/s41565-026-02254-6

Keywords: quantum computing, entanglement, spin register, room temperature, multipartite entanglement, quantum gates, quantum error correction, qubits, quantum nanotechnology, coherence time, quantum sensors, solid-state spins