Since the discovery of superconductivity in MgB₂ (T_c ∼ 39 K), the search for superconductivity in related materials with similar structures or ingredients has never stopped. Although about 100 binary borides have been explored, only a few of them show superconductivity with relatively low T_c. In this work, we report the discovery of superconductivity up to 32 K, which is the highest T_c in transition-metal borides, in MoB₂ under pressure. The T_c of MoB₂ in the α phase can be well explained by theoretical calculations in the framework of electron-phonon coupling. Furthermore, the coupling between the d electrons of Mo and the out-of-plane Mo-phonon modes are the main driving force of the 32 K superconductivity of MoB₂. Our study sheds light on the exploration of high-T_c superconductors in transition metal borides.

Nickelate superconductors have attracted a great deal of attention over the past few decades due to their similar crystal and electronic structures with high-temperature cuprate superconductors. Here, we report superconductivity in a pressurized Ruddlesden-Popper phase single crystal La 4 Ni 3 O 10 ( n = 3 ) and its interplay with the density wave order in the phase diagram. With increasing pressure, the density wave order, as indicated by the anomaly in the resistivity, is progressively suppressed, followed by the emergence of superconductivity around 25 K under the I 4 / m m m space group. The susceptibility measurements confirm bulk superconductivity with a volume fraction exceeding 80%. Moreover, theoretical analysis unveils that antiferromagnetic superexchange interactions can serve as the effective pairing interaction for the emergence of superconductivity in pressurized La 4 Ni 3 O 10 . Our research provides a new platform for the investigation of the unconventional superconductivity mechanism in Ruddlesden-Popper trilayer perovskite nickelates.