Smartphone-enabled colorimetric determination of silver ions exploiting the peroxidase-mimetic behavior of bowl-shaped Pd3Pt nanocrystals

•Bowl-shaped Pd3Pt nanozymes are used as a probe for Ag+ detection.•Ag+ interacts with Pd3Pt nanobowls through the metal affinity and electrostatic attraction.•The Ag+ content in water samples from various sources has been accurately determined.•This sensing approach enables smartphone read-out, making it highly promising for application in point-of-care testing.